The 1999 Arizona Diamondbacks season was the franchise's second season in Major League Baseball and their second season at Bank One Ballpark and in Phoenix, Arizona. They began the season on April 5 at home against the Los Angeles Dodgers, and looked to improve on their 1998 expansion season. They looked to contend in what was a strong National League West. They finished the season with a highly surprising record of 100-62, good enough for the NL West title, becoming the fastest expansion team in MLB history to reach the playoffs. They also set all-time franchise highs in hits (1,566), runs (908), batting average (.277), on-base percentage (.347), and slugging percentage (.459). In the NLDS, however, they fell in four games to the New York Mets on Todd Pratt's infamous home run. Randy Johnson would win the NL Cy Young Award and become the third pitcher to win the Cy Young Award in both leagues.Great Baseball Feats, Facts and Figures, 2008 Edition, p.236, David Nemec and Scott Flatow, A Signet Book, Penguin Group, New York,

Offseason October 26, 1998: Izzy Molina was signed as a free agent with the Arizona Diamondbacks.Izzy Molina Statistics - Baseball-Reference.com November 10, 1998: Dante Powell was traded by the San Francisco Giants to the Arizona Diamondbacks for Alan Embree.Dante Powell Statistics - Baseball-Reference.com November 13, 1998: Greg Swindell signed as a free agent with the Arizona Diamondbacks.Greg Swindell Statistics - Baseball-Reference.com December 2, 1998: Ernie Young was signed as a free agent with the Arizona Diamondbacks. December 10, 1998: Randy Johnson signed as a free agent with the Arizona Diamondbacks.Randy Johnson Statistics - Baseball-Reference.com January 22, 1999: Ken Huckaby was signed as a free agent with the Arizona Diamondbacks.Ken Huckaby Statistics - Baseball-Reference.com February 18, 1999: Dale Sveum was signed as a free agent with the Arizona Diamondbacks. March 30, 1999: Izzy Molina was traded by the Arizona Diamondbacks with Ben Ford to the New York Yankees for Darren Holmes and cash. March 30, 1999: Aaron Small was released by the Arizona Diamondbacks.

Regular season In his first season with the club, Randy Johnson helped the second-year franchise win the NL West title. He joined Gaylord Perry and Pedro Martínez as one of only three pitchers to win Cy Young Awards in both leagues. Johnson led the NL with a 2.48 ERA and led both leagues with 364 strikeouts, 12 complete games and 271 innings pitched.

Opening Day starters Tony Batista Jay Bell Andy Benes Steve Finley Luis Gonzalez Travis Lee Damian Miller Matt Williams Tony Womack 1999 Arizona Diamondbacks Roster by Baseball Almanac

Notable transactions May 9, 1999: Dale Sveum was released by the Arizona Diamondbacks. June 2, 1999: Lyle Overbay was drafted by the Arizona Diamondbacks in the 18th round of the 1999 amateur draft. Player signed June 8, 1999.Lyle Overbay Statistics - Baseball-Reference.com June 12, 1999: Dan Plesac was traded by the Toronto Blue Jays to the Arizona Diamondbacks for Tony Batista and John Frascatore.Dan Plesac Statistics - Baseball-Reference.com

Season standings

Record vs. opponents

Game log Legend Diamondbacks Win Diamondbacks Loss Game postponed

|- style="text-align:center; background:#fbb;" | 1 || April 5 || @ Dodgers || 6–8 (11/wo) || Shaw (1-0) || Frascatore (0-1) || None || Dodger Stadium || 53,109 || 0–1 || |- style="text-align:center; background:#fbb;" | 2 || April 6 || @ Dodgers || 2–3 (10/wo) || Mills (1-0) || Anderson (0-1) || None || Dodger Stadium || 33,139 || 0–2 || |- style="text-align:center; background:#fbb;" | 3 || April 7 || @ Dodgers || 4–6 || Valdez (1-0) || Benes (0-1) || Shaw (1) || Dodger Stadium || 29,042 || 0–3 || |- style="text-align:center; background:#fbb;" | 4 || April 9 || @ Braves || 2–3 (10/wo) || Rocker (1-0) || Frascatore (0-2) || None || Turner Field || 34,939 || 0–4 || |- style="text-align:center; background:#bfb;" | 5 || April 10 || @ Braves || 8–3 || Johnson (1-0) || Glavine (0-2) || None || Turner Field || 44,531 || 1–4 || |- style="text-align:center; background:#fbb;" | 6 || April 11 || @ Braves || 2–3 (wo) || McGlinchy (1-0) || Olson (0-1) || None || Turner Field || 32,454 || 1–5 || |- style="text-align:center; background:#bfb;" | 7 || April 12 || Dodgers || 12–6 || Benes (1-1) || Park (0-1) || None || Bank One Ballpark || 46,929 || 2–5 || |- style="text-align:center; background:#bfb;" | 8 || April 13 || Dodgers || 7–6 (16/wo) || Chouinard (1-0) || Mlicki (0-1) || None || Bank One Ballpark || 31,197 || 3–5 || |- style="text-align:center; background:#bfb;" | 9 || April 14 || Dodgers || 6–2 || Daal (1-0) || Perez (0-2) || None || Bank One Ballpark || 30,561 || 4–5 || |- style="text-align:center; background:#fbb;" | 10 || April 15 || Dodgers || 1–8 || Dreifort (2-0) || Johnson (1-1) || None || Bank One Ballpark || 36,105 || 4–6 || |- style="text-align:center; background:#bfb;" | 11 || April 16 || Giants || 10–4 || Stottlemyre (1-0) || Gardner || Anderson (1) || Bank One Ballpark || 34,516 || 5–6 || |- style="text-align:center; background:#fbb;" | 12 || April 17 || Giants || 5–8 || Rueter (1-0) || Benes (1-2) || None || Bank One Ballpark || 36,674 || 5–7 || |- style="text-align:center; background:#bfb;" | 13 || April 18 || Giants || 12–3 || Reynoso (1-0) || Ortiz (1-2) || None || Bank One Ballpark || 36,043 || 6–7 || |- style="text-align:center; background:#bfb;" | 14 || April 19 || Phillies || 3–2 || Daal (2-0) || Perez (0-1) || Swindell (1) || Bank One Ballpark || 29,704 || 7–7 || |- style="text-align:center; background:#bfb;" | 15 || April 20 || Phillies || 8–1 || Johnson (2-1) || Spoljaric (0-2) || None || Bank One Ballpark || 30,546 || 8–7 || |- style="text-align:center; background:#bfb;" | 16 || April 21 || Phillies || 4–2 || Stottlemyre (2-0) || Schilling (3-1) || Olson (1) || Bank One Ballpark || 31,421 || 9–7 || |- style="text-align:center; background:#bfb;" | 17 || April 23 || @ Padres || 10–6 || Benes (2-2) || Hitchcock (1-1) || None || Qualcomm Stadium || 20,437 || 10–7 || |- style="text-align:center; background:#fbb;" | 18 || April 24 || @ Padres || 2–7 || Williams (1-0) || Daal (2-1) || None || Qualcomm Stadium || 61,674 || 10–8 || |- style="text-align:center; background:#bfb;" | 19 || April 25 || @ Padres || 5–3 (11) || Swindell (1-0) || Miceli (1-1) || Olson (2) || Qualcomm Stadium || 26,684 || 11–8 || |- style="text-align:center; background:#fbb;" | 20 || April 26 || @ Astros || 2–5 || Lima (3-1) || Stottlemyre (2-1) || Wagner (6) || Astrodome || 18,328 || 11–9 || |- style="text-align:center; background:#fbb;" | 21 || April 27 || @ Astros || 0–11 || Reynolds (4-1) || Reynoso (1-1) || None || Astrodome || 19,396 || 11–10 || |- style="text-align:center; background:#bfb;" | 22 || April 28 || @ Astros || 10–6 || Holmes (1-0) || Wagner (1-1) || None || Astrodome || 19,605 || 12–10 || |- style="text-align:center; background:#fbb;" | 23 || April 29 || @ Astros || 2–5 || Hampton (2-1) || Daal (2-2) || Wagner (7) || Astrodome || 21,506 || 12–11 || |- style="text-align:center; background:#bfb;" | 24 || April 30 || @ Brewers || 3–2 || Holmes (2-0) || Myers (1-1) || Olson (3) || Milwaukee County Stadium || 17,008 || 13–11 ||

|- style="text-align:center; background:#bfb;" | 25 || May 1 || @ Brewers || 5–3 || Stottlemyre (3-1) || Abbott (0-4) || Olson (4) || Milwaukee County Stadium || 28,415 || 14–11 || |- style="text-align:center; background:#fbb;" | 26|| May 2 || @ Brewers || 5–6 || Weathers (2-0) || Holmes (2-1) || None || Milwaukee County Stadium || 13,943 || 14–13 || |- style="text-align:center; background:#fbb;" | 27|| May 3 || @ Reds || 3–4 (wo) || Williamson (2-1) || Olson (0-2) || Wickman (4) || Cinergy Field || 23,811 || 14–12 || |- style="text-align:center; background:#fbb;" | 28|| May 4 || @ Reds || 4–6 || Reyes (1-0) || Daal (2-3) || Graves (4) || Cinergy Field || 14,660 || 14–14 || |- style="text-align:center; background:#bfb;" | 29|| May 5 || @ Reds || 5–1 || Johnson (3-1) || Avery (1-3) || None || Cinergy Field || 16,247 || 15–14 || |- style="text-align:center; background:#bfb;" | 30|| May 7 || Mets || 14–7 || Stottlemyre (4-1) || Hershiser (2-3) || None || Bank One Ballpark || 38,154 || 16–14 || |- style="text-align:center; background:#fbb;" | 31|| May 8 || Mets || 2–4 || Yoshii (2-3) || Benes (2-3) || Benitez (1) || Bank One Ballpark || 37,593 || 16–15 || |- style="text-align:center; background:#bfb;" | 32|| May 9 || Mets || 11–6 || Daal (3-3) || Reed (2-1) || None || Bank One Ballpark || 38,250 || 17–15 || |- style="text-align:center; background:#bfb;" | 33|| May 10 || Expos || 7–6 (wo) || Olson (1-2) || Ayala (0-3) || None || Bank One Ballpark || 31,208 || 18–15 || |- style="text-align:center; background:#bfb;" | 34|| May 11 || Expos || 4–3 (10/wo) || Olson (2-2) || Mota (0-1) || None || Bank One Ballpark || 28,103 || 19–15 || |- style="text-align:center; background:#bfb;" | 35|| May 12 || Expos || 8–6 (wo) || Telemaco (1-0) || Smart (0-1) || None || Bank One Ballpark || 30,753 || 20–15 || |- style="text-align:center; background:#fbb;" | 36|| May 14 || Rockies || 1–4 || Bohanon (6-1) || Benes (2-4) || None || Bank One Ballpark || 38,894 || 20–16 || |- style="text-align:center; background:#bfb;" | 37|| May 15 || Rockies || 9–2 || Johnson (4-1) || Kile (2-3) || None || Bank One Ballpark || 40,853 || 21–16 || |- style="text-align:center; background:#fbb;" | 38|| May 16 || Rockies || 1–5 || Astacio (4-3) || Daal (3-4) || None || Bank One Ballpark || 38,869 || 21–17 || |- style="text-align:center; background:#bfb;" | 39|| May 17 || @ Giants || 12–1 || Frascatore (1-2) || Estes (2-3) || None || 3Com Park || 10,846 || 22–17 || |- style="text-align:center; background:#bfb;" | 40|| May 18 || @ Giants || 7–3 || Reynoso (2-1) || Brock (4-3) || None || 3Com Park || 10,900 || 23–17 || |- style="text-align:center; background:#fbb;" | 41|| May 19 || @ Giants || 3–8 || Rueter (3-2) || Benes (2-5) || None || 3Com Park || 15,793 || 23–18 || |- style="text-align:center; background:#fbb;" | 42|| May 20 || @ Rockies || 4–8 || Kile (3-3) || Johnson (4-2) || None || Coors Field || 40,021 || 23–19 || |- style="text-align:center; background:#fbb;" | 43|| May 21 || @ Rockies || 7–8 (11/wo) || Leskanic (1-1) || Frascatore (1-3) || None || Coors Field || 44,205 || 23–20 || |- style="text-align:center; background:#bfb;" | 44|| May 22 || @ Rockies || 8–3 || Daal (4-4) || Jones (1-3) || None || Coors Field || 48,594 || 24–20 || |- style="text-align:center; background:#fbb;" | 45|| May 23 || @ Rockies || 6–7 (wo) || McElroy (2-0) || Olson (2-3) || None || Coors Field || 46,299 || 24–21 || |- style="text-align:center; background:#bfb;" | 46|| May 24 || Padres || 6–5 || Benes (3-5) || Ashby (5-3) || Olson (5) || Bank One Ballpark || 34,745 || 25–21 || |- style="text-align:center; background:#bfb;" | 47|| May 25 || Padres || 4–0 || Johnson (5-2) || Hitchcock (3-4) || None || Bank One Ballpark || 34,273 || 26–21 || |- style="text-align:center; background:#bfb;" | 48|| May 26 || Padres || 3–2 (11/wo) || Olson (3-3) || Miceli (2-2) || None || Bank One Ballpark || 33,048 || 27–21 || |- style="text-align:center; background:#bfb;" | 49|| May 28 || @ Mets || 2–1 || Daal (5-4) || Reed (3-2) || Olson (6) || Shea Stadium || 32,114 || 28–21 || |- style="text-align:center; background:#bfb;" | 50|| May 29 || @ Mets || 8–7 || Reynoso (3-3) || Beltran (1-1) || Kim (1) || Shea Stadium || 35,167 || 29–21 || |- style="text-align:center; background:#bfb;" | 51|| May 30 || @ Mets || 10–1 || Johnson (6-2) || Yoshii (5-4) || None || Shea Stadium || 38,302 || 30–21 || |- style="text-align:center; background:#bfb;" | 52|| May 30 || @ Expos || 8–5 (10) || Holmes (3-1) || Kline (1-2) || Olson (7) || Olympic Stadium || 5,048 || 31–21 ||

|- style="text-align:center; background:#fbb;"