The first generation (generation I) of the Pokémon franchise features the original 151 fictional species of monsters introduced to the core video game series in the 1996 Game Boy games Pocket Monsters Red, Green and Blue (known as Pokémon Red, Green and Blue outside of Japan). Later, Pokémon Yellow and Blue were released in Japan.

The following list details the 151 Pokémon of generation I in order of their National Pokédex number. The first Pokémon, Bulbasaur, is number 0001 and the last, Mew, is number 0151. Alternate forms that result in type changes are included for convenience. Mega evolutions and regional forms are included on the pages for the generation in which they were introduced. MissingNo., a glitch, is also on this list.

Design and development Pokémon are a species of fictional creatures created for the Pokémon media franchise. Developed by Game Freak and published by Nintendo, the Japanese franchise began in 1996 with the video games Pokémon Red and Green for the Game Boy, which were later released in North America as Pokémon Red and Blue in 1998. In these games and their sequels, the player assumes the role of a Trainer whose goal is to capture and use the creatures' special abilities to combat other Pokémon. Some Pokémon can transform into stronger species through a process called evolution via various means, such as through battling or exposure to specific items. Each Pokémon have one or two elemental types, which define its advantages and disadvantages when battling other Pokémon. A major goal in each game is to complete the Pokédex, a comprehensive Pokémon encyclopedia, by capturing Pokémon, evolving them, and trading with other Trainers to obtain individuals from all Pokémon species.

The designs of each Pokémon started as pixel art sprites by the development team first, with a single color identity chosen to work within the Super Game Boy hardware limitations. With the early development team consisting of three men, character design lead Ken Sugimori brought female developers into the project feeling they would be better able to create "cute" designs. While conceived as a group effort by multiple developers at Game Freak, the finalized designs and artworks were done by Sugimori. Originally tasked with drawing the characters to illustrate a planned strategy guide by Game Freak when the games released, Sugimori drew all the sprites for the game in his style to not only unify their designs visually, but also modify any design elements he felt were amiss, while trying to retain the original sprite artist's unique style. While some Pokémon have been attributed to certain developers over the years, such as Atsuko Nishida for Pikachu and Motofumi Fujiwara for Eevee and its evolutions, Game Freak has avoided attributing many Pokémon to particular individuals to keep a sense of all the developers being involved in their creation.

The majority of Pokémon in generation I had relatively simple designs and were similar to real-life creatures including Pidgey (a pigeon), Krabby (a crab), Rattata (a rat), and Ekans (a snake). Many Pokémon in the original games served as the base for repeating concepts later in the series. Some Pokémon, such as Squirtle, Bulbasaur and Charmander were designed based on their final evolutions and working backwards. During development they ran into issues with digital cartridge space, and many Pokémon were removed. Specifically, several Pokémon that had a three-stage evolution line were instead changed to evolve only once, resulting in a planned final evolution for Pikachu called "Gorochu" being removed from the final game.

When the games were localized for English-speaking audiences as Red and Blue, Nintendo of America gave the various Pokémon species "clever and descriptive names" related to their appearance or features as a means to make them more relatable to American children. This resulted in several pop-culture references being worked into the character's names, such as Hitmonchan and Hitmonlee, who are references to martial arts actors Jackie Chan and Bruce Lee respectively. Overseen by translator Nob Ogasawara, he voiced concern over some of the choices presented, specifically "Barrierd", which was renamed to "Mr. Mime" based on its masculine appearance. Ogasawara wanted to avoid gendered, binary names for the Pokémon species in the event genders were introduced for them in later titles, a concern proven valid with the sequel titles Pokémon Gold and Silver.

List of Pokémon

Bulbasaur Ivysaur Venusaur Charmander Charmeleon Charizard Squirtle Wartortle Blastoise Caterpie Metapod Butterfree Weedle Kakuna Beedrill Pidgey Pidgeotto Pidgeot Rattata Raticate Spearow Fearow Ekans Arbok Pikachu Raichu Sandshrew Sandslash Nidoran♀ Nidorina Nidoqueen Nidoran♂ Nidorino Nidoking Clefairy Clefable Vulpix Ninetales Jigglypuff Wigglytuff Zubat Golbat Oddish Gloom Vileplume Paras Parasect Venonat Venomoth Diglett Dugtrio Meowth Persian Psyduck Golduck Mankey Primeape Growlithe Arcanine Poliwag Poliwhirl Poliwrath Abra Kadabra Alakazam Machop Machoke Machamp Bellsprout Weepinbell Victreebel Tentacool Tentacruel Geodude Graveler Golem Ponyta Rapidash Slowpoke Slowbro Magnemite Magneton Farfetch'd Doduo Dodrio Seel Dewgong Grimer Muk Shellder Cloyster Gastly Haunter Gengar Onix Drowzee Hypno Krabby Kingler Voltorb Electrode Exeggcute Exeggutor Cubone Marowak Hitmonlee Hitmonchan Lickitung Koffing Weezing Rhyhorn Rhydon Chansey Tangela Kangaskhan Horsea Seadra Goldeen Seaking Staryu Starmie Mr. Mime Scyther Jynx Electabuzz Magmar Pinsir Tauros Magikarp Gyarados Lapras Ditto Eevee Vaporeon Jolteon Flareon Porygon Omanyte Omastar Kabuto Kabutops Aerodactyl Snorlax Articuno Zapdos Moltres Dratini Dragonair Dragonite Mewtwo Mew MissingNo.

List of Pokémon species introduced in generation I (1996) Name Type(s) Evolves from Evolves into Notes Bulbasaur(0001) ||align=center| Grass / Poison Ivysaur (#0002) Bulbasaur is one of Kanto's starter Pokémon. It has a bulb on its back, which stores nutrients. Since the bulb can photosynthesize, Bulbasaur can go days without eating. As with the rest of its evolutionary line, its bulb has vines the Pokémon uses as tentacles. Ivysaur(0002) ||align=center| Grass / Poison Bulbasaur (#0001) Venusaur (#0003) Ivysaur is a playable character in Super Smash Bros. Brawl and Super Smash Bros. Ultimate as a part of the "Pokémon Trainer" fighter. Its bulb has grown into a bud, which it uses to convert sunlight into power. The bud is heavy, to the point of rendering Ivysaur unable to move properly if it has stored enough nutrients, so its hind legs have grown stronger to counter the weight. Venusaur(0003) ||align=center| Grass / Poison Ivysaur (#0002) Mega EvolutionGigantamax The mascot of Pokémon Green and LeafGreen. The bud on its back has bloomed into a flower. It has a soothing aroma, and converts sunlight into energy. For this reason, Venusaur is more powerful during the summer. It gained a Mega Evolution in generation VI, and a Gigantamax form in generation VIII. Charmander(0004) ||align=center| Fire Charmeleon (#0005) Charmander is one of Kanto's starter Pokémon. A flame burns at the tip of its tail from the moment it hatches. Still unfamiliar with fire, a Charmander might accidentally burn itself. If its flame goes out, it dies. Charmeleon(0005) ||align=center| Fire Charmander (#0004) Charizard (#0006) A feisty Pokémon, it seeks out potential opponents and torments them in battle. It attacks by spewing fire from its mouth, swinging its tail around, or clawing away. Its fire turns bluish-white when it is excited. Charizard(0006) ||align=center| Fire / Flying Charmeleon (#0005) Two Mega EvolutionsGigantamax Charizard is a playable character as a part of the "Pokémon Trainer" fighter in Super Smash Bros. Brawl and Super Smash Bros. Ultimate, a standalone fighter in Super Smash Bros. for Nintendo 3DS and Wii U, and the mascot of Pokémon Red and FireRed. Its fire is hot enough to melt boulders and glaciers, and it is known to start forest fires by accident, though it will not use it against weaker foes. The flame on its tail can burn underwater, and turns bluish-white if Charizard is angry. It gained two Mega Evolutions in generation VI, one Fire/Flying-type and one Fire/Dragon-type, and a Gigantamax form in generation VIII. Squirtle(0007) ||align=center| Water Wartortle (#0008) It is a playable character in Super Smash Bros. Brawl and Super Smash Bros. Ultimate as a part of the "Pokémon Trainer" fighter, and one of Kanto's starter Pokémon. After it hatches, its back gradually swells and hardens into a shell. It withdraws into its shell for protection or to sleep, and its grooved, rounded shape reduce its water resistance, allowing it to swim faster. To attack, it sprays foamy water from its mouth. Wartortle(0008) ||align=center| Water Squirtle (#0007) Blastoise (#0009) Because it is bigger and heavier than Squirtle, it has trouble walking, and has to use its furry ears and tail as rudders and balancing rods to swim. It withdraws into its shell to attack, defend itself, and sleep, though it cannot fully withdraw its tail. It is said to be able to live for up to 10,000 years. Older Wartortle have darker tail fur, and may have scars and algae on their shells. Blastoise(0009) ||align=center| Water Wartortle (#0008) Mega EvolutionGigantamax It is the mascot of Pokémon Blue. The two cannons on its shell shoot out pressurized jets of water strong enough to shatter thick steel walls, and accurate enough to hit empty cans from over 160 feet away. Blastoise itself can tackle at high speeds. A cruel Pokémon, it deliberately makes itself heavier to withstand its cannons' recoil and crush its opponents. It gained a Mega Evolution in generation VI and a Gigantamax form in generation VIII. A Blastoise trading card, which was originally made as a test print before the commercial English cards, was sold for $360,000 in 2021. Caterpie(0010) ||align=center| Bug Metapod (#0011) Its feet have suction pads that allow it to climb slopes, walls, and trees. To protect itself, it releases a stench from its antennae. It camouflages itself in piles of leaves, or tries to scare predators with the eye patterns on its body. Across its life, it eats hundreds of leaves, some bigger than itself. When nearing evolution, it sheds its skin, covers itself with silk, and becomes a cocoon. Metapod(0011) ||align=center| Bug Caterpie (#0010) Butterfree (#0012) Though hard, Metapod's shell is said to be easy to break open, so it hardens it further when threatened to avoid spilling its thick, liquid innards. It waits for evolution while its cells restructure. Ume Aoki, a Japanese cartoonist who is famous for her work on the manga Hidamari Sketch and the anime Puella Magi Madoka Magica, utilizes a likeness of herself cosplaying as a Metapod in her drawn works. Butterfree(0012) ||align=center| Bug / Flying Metapod (#0011) GigantamaxIts wings are covered in poisonous, water-repelling powder, which it uses to defend itself and fly in the rain. It goes from flower to flower to collect nectar, and rubs honey onto the hairs of its legs to carry back to its nest. It spreads its scales around to defend nearby Caterpie from predators. It competes with Cutiefly for territory. It gained a Gigantamax form in generation VIII. Weedle(0013) ||align=center| Bug / Poison Kakuna (#0014) A common sight in forests and grassy areas, it has a two-inch poisonous stinger on its head, which it uses to defend itself. It has an acute sense of smell, being able to distinguish leaves it likes from those it dislikes with its big nose. It eats its weight in leaves every day. Kakuna(0014)