Counter-Strike: Source Cheat Codes

Main Cheat Codes

NOTE: These are the main Counter-Strike: Source cheats that are usually applied by pressing down the right key combination. Please find the instructions on how to use these cheats below. Press [~] during game play to display the console window. Then, type sv_cheats 1 to enable cheat mode. Then, enter one of the following codes to activate the corresponding cheat function:

cl_cmdrate 1 - Makes ping appear low, but doesn't affect actual ping
cl_crosshairscale 5000 - Makes your crosshair really small (default unknown)
cl_sidespeed 3500 - Allows you to move at the set diagonal speed

All of the above cheats must be entered from the host machine. Host machine must have sv_cheats set to 1 (sv_cheats 1).

mp_limitteams 0 - Prevents team pile-up restriction
mp_autoteambalance 0 - Prevents the automatic balance of teams on the next round
noclip - Fly through the map
notarget - Bots can't detect you
mat_wireframe 1 - Wireframe view of world
mat_fullbright 1 - Makes the map bright (useful on de_dust and de_prodigy)
cl_drawhud 0 - Removes HUD including gun and health
cl_forwardspeed 5000 - Time compression on
cl_backspeed 5000 - Time compression off
impulse 101 - Gives full ammo for weapons on hand
impulse 99 - Skulls drop from sky

bot_add_t - Add bot for team (terrorist)
bot_add_ct - Add bot for that team (counter-terrorist)
bot_allow_shotguns <0 or 1> - Allow/disallow bots to use Shotguns
bot_allow_snipers <0 or 1> - Allow/disallow bots to use Snipers
bot_allow_pistols <0 or 1> - Allow/disallow bots to use Pistols
bot_allow_grenades <0 or 1> - Allow/disallow bots to use Grenades
bot_allow_rifles <0 or 1> - Allow/disallow bots to use Rifles
bot_allow_sub_machine_guns <0 or 1> - Allow/disallow bots to use SMGs
bot_allow_machine_guns <0 or 1> - Allow/disallow bots to use Machine Guns
bot_zombie 1 - Bots don't move but will shoot
bot_dont_shoot 1 - Bots don't shoot weapons
bot_knives_only - Bots do not use weapons but use knives and grenades
bot_pistols_only - Bots fire pistols and grenades
bot_snipers_only - Bots fire sniper rifles and grenades
bot_allow_rogue <0 or 1> - Bots use teamwork or go lone wolf
bot_all_weapons - Bots use all weapons
bot_kick - Remove all bots from server
bot_kill - Kills all bots on server (may not boot them from game)
changelevel

Reference: http://www.actiontrip.com/cheats/counterstrikesource.phtml