001 Bulbasaur - House in Cerulean City
002 Ivysaur - Evolve Bulbasaur (16)
003 Venusaur - Evolve Venusaur (32)
004 Charmander - Route 24 from Man
005 Charmeleon - Evolve Charmander (16)
006 Charizard - Evolve Charmeleon (36)
007 Squirtle - Woman in Vermillion (after Gym battle)
008 Wartortle - Evolve Squirtle (16)
009 Blastoise - Evolve Wartortle (36)
010 Caterpie - Viridian Forest
011 Metapod - Evolve Caterpie (7)
012 Butterfree - Evolve Metapod (10)
013 Weedle - Routes 2, 24, 25
014 Kakuna - Evolve Weedle (7)
015 Beedrill - Evolve Kakuna (10)
016 Pidgey - Routes 1, 2, 7, 17, 22
017 Pidgeotto - Evolve Pidgey (18)
018 Pidgeot - Evolve Pidgeotto (36)
019 Rattata - Routes 11, 12, 13, 14, 15, 18
020 Raticate - Evolve Rattata (20)
021 Spearow - Routes 6, 13, 14, 15, 18
022 Fearow - Evolve Spearow (20)
023 Ekans - Routes 1, 2, 3, 4, 17, 22
024 Arbok - Evolve Ekans (22)
025 Pikachu - *Starter Pokemon (surfing)
026 Raichu - Trade Eevee in Cinnabar (surfing)
027 Sandshrew - Mount Moon
028 Sandslash - Evolve Sandshrew (22)
029 Nidoran (F) - Routes 13, 14, 15; Safari Zone
030 Nidorina - Evolve Nidoran F (16)
031 Nidoqueen - Evolve Nidorina (Moon Stone)
032 Nidoran (M) - Routes 13, 14, 15; Safari Zone
033 Nidorino - Evolve Nidoran M (16)
034 Nidoking - Evolve Nidorino (Moon Stone)
035 Clefairy - Mount Moon
036 Clefable - Evolve Clefairy (Moon Stone)
037 Vulpix - Route 16; Celadon Game Corner
038 Ninetales - Evolve Vulpix (Fire Stone)
039 Jigglypuff - Route 22
040 Wigglytuff - Evolve Jigglypuff (Moon Stone)
041 Zubat - Mount Moon, Rock Tunnel, Seafoam Cave, Victory Road
042 Golbat - Evolve Zubat (22)
043 Oddish - Routes 2, 3, 4, 5, 7, 24, 25
044 Gloom - Evolve Oddish (21)
045 Vileplume - Evolve Gloom (Leaf Stone)
046 Paras - Mount Moon, Safari Zone
047 Parasect - Evolve Paras (24)
048 Venonat - Routes 13, 14, 15
049 Venomoth - Evolve Venonat (31)
050 Diglett - Diglett's Cave
051 Dugtrio - Evolve Diglett (26)
052 Meowth - Routes 4, 24, 25
053 Persian - Evolve Meowth (28)
054 Psyduck - Surf in Route 6
055 Golduck - Evolve Psyduck (33)
056 Mankey - Routes 3, 22
057 Primeape - Evolve Mankey (28)
058 Growlithe - Route 16; Pokemon Mansion
059 Arcanine - Evolve Growlithe (Fire Stone)
060 Poliwag - Fish in Routes 16, 17, 22, 23, Viridian, Fuschia
061 Poliwhirl - Evolve Poliwag (25)
062 Poliwrath - Evolve Poliwhirl (Water Stone)
063 Abra - Route 24; Celadon Game Corner
064 Kadabra - Evolve Abra (16)
065 Alakazam - Trade Kadabra at Route 5
066 Machop - Routes 9, 10; Rock Tunnel
067 Machoke - Evolve Machop (28)
068 Machamp - Trade Machoke at Route 2
069 Bellsprout - Routes 6, 8, 11, 12, 13, 14, 15
070 Weepinbell - Evolve Bellsprout (21)
071 Victreebel - Evolve Weepinbell (Leaf Stone)
072 Tentacool - Fish in Route 11, Pallet, Vermilion, Seafoam; Surf in Routes 19, 20, 21
073 Tentacruel - Evolve Tentacool (30)
074 Geodude - Mount Moon, Rock Tunnel, Victory Road
075 Graveler - Evolve Geodude (25)
076 Golem - Trade Graveler at Route 11
077 Ponyta - Route 16
078 Rapidash - Evolve Ponyta (40)
079 Slowpoke - Surf Routes 12, 13, Seafoam
080 Slowbro - Evolve Slowpoke (37)
081 Magnemite - Power Plant
082 Magneton - Evolve Magnemite (30)
083 Farfetch'd - Routes 8, 9, 10, 11, 12, 17
084 Doduo - Routes 3, 4, 5, 18, 24, 25
085 Dodrio - Evolve Doduo (31)
086 Seel - Seafoam Island
087 Dewgong - Evolve Seel (34)
088 Grimer - Pokemon Mansion, Power Plant
089 Muk - Evolve Grimer (38)
090 Shellder - Fish in Routes 16, 17
091 Cloyster - Evolve Shellder (Water Stone)
092 Gastly - Pokemon Tower
093 Haunter - Evolve Gastly (25)
094 Gengar - Trade Haunter at Route 18
095 Onix - Rock Tunnel, Victory Road
096 Drowzee - Route 17
097 Hypno - Evolve Drowzee (26)
098 Krabby - Fish in Routes 9, 24, 25; Seafoam
099 Kingler - Evolve Krabby (28)
100 Voltorb - Power Plant
101 Electrode - Evolve Voltorb (30)
102 Exeggcute - Safari Zone
103 Exeggutor - Evolve Exeggcute (Leaf Stone)
104 Cubone - Safari Zone, Pokemon Tower
105 Marowak - Evolve Cubone (28)
106 Hitmonlee - Route 23; Saffron City Dojo
107 Hitmonchan - Route 23; Saffron City Dojo
108 Lickitung - Route 12; Unknown Dungeon
109 Koffing - Routes 9, 10
110 Weezing - Evolve Koffing (35)
111 Rhyhorn - Safari Zone, Unknown Dungeon
112 Rhydon - Evolve Rhyhorn (42)
113 Chansey - Safari Zone, Unknown Dungeon
114 Tangela - Safari Zone
115 Kangaskhan - Safari Zone
116 Horsea - Fish in Routes 12, 13
117 Seadra - Evolve Horsea (32)
118 Goldeen - Fish Anywhere (Good Rod)
119 Seaking - Evolve Goldeen (33)
120 Staryu - Fish in Routes, 19, 20, 21, Pallet Town; Surf in Seafoam
121 Starmie - Evolve Staryu (Water Stone)
122 Mr. Mime - Routes 7, 8
123 Scyther - Safari Zone
124 Jynx - Routes 5, 6
125 Electabuzz - Route 10
126 Magmar - Route 16
127 Pinsir - Safari Zone
128 Tauros - Safari Zone
129 Magikarp - Fish Anywhere
130 Gyarados - Evolve Magikarp (20)
131 Lapras - Silph Co. in Lavendar
132 Ditto - Pokemon Mansion, Unknown Dungeon
133 Eevee - Route 23; Celadon Mansion
134 Vaporeon - Evolve Eevee (Water Stone)
135 Jolteon - Evolve Eevee (Thunder Stone)
136 Flareon - Evolve Eevee (Fire Stone)
137 Porygon - Celadon Game Corner
138 Omanyte - Route 23; Cinnabar Lab
139 Omastar - Evolve Omanyte (40)
140 Kabuto - Route 23; Cinnabar Lab
141 Kabutops - Evolve Kabuto (40)
142 Aerodactyl - Cinnabar Lab
143 Snorlax - Routes 12, 16 (PokeFlute); Trade Eevee in Cinnabar
144 Articuno - Seafoam Islands (Battle)
145 Zapdos - Power Plant (Battle)
146 Moltres - Victory Road (Battle)
147 Dratini - Fish in the Safari Zone
148 Dragonair - Evolve Dratini (30)
149 Dragonite - Evolve Dragonair (55)
150 Mewtwo - Unknown Dungeon (Battle)
151 Mew - Route 24*, Trade Eevee in Cinnabar
*To catch Mew, you must not have beaten the Cerulean City Gym or crossed Gate Bridge.
Across Gate Bridge, there is a trainer to the left in the patch of grass you have to avoid for now. You must catch an Abra for its Teleport ability, so you will need to have a pokemon with a sleep ability in your party. Save your game, make sure you have some Poke Balls, and go over to the trainer in the grass to the left of Gate Bridge, but do not challenge him yet. Stand directly to the north of the trainer so he's out of sight. Walk south, holding down start and the menu will come up before the [!] appears over his head. Use Teleport to get back to the Cerulean PokeCenter, and if you've done it correctly, your buttons should be disabled. Without talking to anyone, enter the Cerulean Gym and battle the Swimmer. After you defeat him, go back to the Gate Bridge and cross over. Your menu will come up by itself this time! Press B and you'll automatically enter a battle with a wild Mew.
Other rare Pokemon can be summoned using the same method by simply avoiding a confrontation with the initial trainer.
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