In order to beat any gym leaders, you will need the right Pokémon, but the Pokémon that you use are only as good as their skill level. This guide will tell you what Pokémon to use in what gym, and how well those Pokémon need to be trained to succeed.
Gym Leaders
Brock - Pewter Gym
| Brock
uses Onix and Geodude, both of which are rock type Pokémon.
Electric attacks are weak against rock Pokémon, as will fire.
You will need a water or grass Pokémon to take out Brock. If
you don't have a grass or water Pokémon, try using poison, the next
best choice. If you need to resort to poison attacks, use a bug from
the Viridian City Forest that knows Poison Sting. Weedle
or an evolution of Weedle would be a good choice. Below is a list of
Brock's Pokémon;
Geodude - Level 12 Onix - Level 14 |
 |
Misty - Cerulean City
|
Misty uses Water type Pokémon. If you caught a Pikachu
in the Viridian City Forest, and you will probably need to, you can beat
Misty with no problem. Also, grass Pokémon have strong attacks
against Misty, but poison hardly effects her water Pokémon. Here
is a list of Misty's Pokémon;
Staryu - Level 18 Starmie - Level 21 |
 |
Lieutennant Surge - Vermilion City
|
Lieutennant Surge uses electric Pokémon, as his name suggests. Your
best bet is to stay away from using water and flying Pokémon, and
use ground Pokémon, such as Diglett. Ground Pokémon are
immune to electricity, and can only be hurt by Surge's limited normal attacks,
such as swift. Here is a list of Surge's Pokémon;
Voltorb - Level 21 Pikachu - Level 18 Raichu - Level 24 |
 |
Koga - Fuschia City
| Koga
uses poison Pokémon. Bug and grass Pokémon are your best
bet. If you have Bulbasaur (or evolved form), his attacks such as Vine Whip
will work well. If you have a high level Beedrill, he will be especially
handy. Not only will his bug-based attacks such as Twin Needle be
effective, but since he is part poison, he will be immune to poisonous attacks!
Koga has the following Pokémon:
Koffing - Level 37 Muk - Level 39 Koffing - Level 37 Weezing - Level 43 |
 |
Erika - Celadon City
| Erika
uses grass Pokémon. One of her Pokémon are also of the
poison type. If you have gotten a Vulpix from the outer edges of Celadon
City, you should use it on Erika. Also, be careful that you do not
use a water Pokémon against Erika. Flying, poison, bug, and
ice are all excellent choices in a battle against Erika. Her Pokémon
of choice are as follows;
Victreebell - Level 29 Tangela - Level 24 Vileplume - Level 29 |
 |
Sabrina - Saffron City
| Sabrina
is a master at handling psychic Pokémon. Her Pokémon
are stron against normal and fighting moves. Her Pokémon will
commonly use moves such as Confusion that will make your Pokémon have
a hard time placing an attack, and might just end up hurting themselves.
The only help you can get are from bug and ghost Pokémon, which will
not be as weakened by psychic moves. Sabrina's Pokémon are as
follows;
Kadabra - Level 38 Mr. Mime - Level 37 Venomoth - Level 38 Alakazam - Level 43 |
 |
Blaine - Cinnabar Island
| Blaine
uses fire Pokémon. You should stay away from using grass
Pokémon. Water Pokémon will be good against Blaine.
You can find good water Pokémon in the seas and in Seafoam Islands.
If you miraculously got a Magikarp to evolve into Gyarados, he will
profe a formidable opponent for Blaine's Pokémon. Down below
is a list of the four Pokémon that Blaine uses;
Growlithe - Level 42 Ponyta - Level 40 Rapidash - Level 42 Arcanine - Level 47 |
 |
Giovanni - Viridian City
| Giovanni
is the last gym leader you will face, and he uses rock and ground Pokémon.
Electric Pokémon are definitely not a good choice for battling
Giovanni, but water, grass, and ice Pokémon are excellent choices.
Goivanni has some pretty hard Pokémon lined up, so be
sure your Pokémon are up to level before taking him on. Here
are the Pokémon you will need to fight;
Rhyhorn - Level 45 Dugtrio - Level 42 Nidoqueen - Level 43 Nidoking - Level 45 Rhydon - Level 50 |
 |
The Elite Four
Before you battle the elite four, make sure you have the following types of Pokémon with you, and they are at least at level 70. It is strongly recommended that you have them at level 75 or 80 though. Please note that it is only important that you have the fire Pokémon in the first position, as you will battle ice Pokémon first. You will have to switch the order before you battle every master.
Fire - 1st position
Water - 2nd position
Psychic - 3rd Position
Dragon - 4th position
Electric - 5th position
Grass - 6th position
Lorelei - Elite Four
Lorelei uses ice pokémon. Be sure to stay away from using grass Pokémon against Lorelei. Good choices are fire, fighting, or rock are good choices. Lorelei will be using the following Pokémon;
Dewgong - Level 54
Cloyster - Level 53
Slowbro - Level 54
Jynx - Level 56
Lapras - Level 56
Bruno - Elite Four
Bruno uses fighting and rock Pokémon. His lineup is Onix, Hitmonchan, Hitmonlee, Onix, and Machamp. For the rock Pokémon, you will want to use either your water or grass Pokémon. Be sure to keep the water or grass on top, as you will battle Onix first. For Hitmonchan, Hitmonlee, and Machamp, use a psychic Pokémon. A flying type Pokémon would also work for Bruno's fighting Pokémon. There are the Pokémon Bruno uses, in order;
Onix - Level 53
Hitmonchan - Level 55
Hitmonlee - Level 55
Onix - Level 56
Machamp - Level 58
Agatha - Elite Four
You will battle ghost Pokémon in this battle. Water and fire will be effective against her Pokémon. She will be using Gengar, Golbat, Haunter, Arbok, and another Gengar. Make sure you have lots of powerups and your fire and water Pokémon at the top of the list. Moves like Surf, Fire Blast, Fire Spin, and Water Gun will be useful in this match. Here is Agatha's Lineup;
Gengar - Level 56
Golbat - Level 56
Haunter - Level 55
Arbok - Level 58
Gengar - Level 60
Lance - Elite Four
Lance is the final battle in the Elite Four and the most difficult. You will want to use your dragon Pokémon against his, which are the same type. Keep in mind that this will be a hard fight as you are both using dragon types, which will both be effective against each other. If your water Pokémon knows an ice move, it may come in handy too. Lance will be using Gyarados, two Dragonairs, an Aerodactyl, and Dragonite in battle. Make sure you have plenty of powerups for this battle. You will be battling these Pokemon;
Gyarados - Level 58
Dragonair - Level 56
Dragonair - Level 56
Aerodactyl - Level 60
Dragonite - Level 62
Gary
Remember that Gary will have is team assembled according to the Pokémon that he chose at the beginning. No matter what, he will have with him Pidgeot, Alakazam, and Rhydon. The last three depends on what Pokémon he chose at the beginning. You will want to use your electric Pokémon against his Pidgeot, for Alakazam, you are going to want to use something with a poison attack, and for Rhydon, either your Water or Grass Pokémon. Look forward for more information on the rest of his team according to the Pokémon he chose at the beginning. Use your intuition on what Pokémon to use for the last three listed below;
Gary chose Bulbasaur
Gyarados - Level 61
Arcanine - Level 63
Venusaur - Level 65
Gary chose Charmander
Exeggutor - Level 61
Gyarados - Level 63
Charizard - Level 65
Gary chose Squirtle
Arcanine - Level 61
Exeggutor - Level 63
Blastoise - Level 65
Hopefully this will help you to train your Pokémon correctly to beat all of the gym leaders, elite four, and Gary. If you think anything is missing, please tell me so I can fix it.