Cheat mode
While playing the game, press Up to display Niko's cell phone. Press Up again to access the keypad. Then, enter one of the following codes to activate the corresponding cheat function. Once a code has been entered correctly, a new "Cheats" menu option will be available on your phone, below "Options", where you can access the cheats without having to enter the phone number again. Note: Do not save the game after enabling a code to avoid unforeseen problems. Enabling some cheats will prevent the indicated achievement(s) from being earned. You can usually only spawn one vehicle at a time. Any previously spawned vehicles will disappear. However, if you spawn a vehicle, save the game, and load again, you can spawn another one and your original will not disappear. You must have it in your parking space in front of a safehouse or it will be gone before you have a chance to spawn another.

Full health and armor
Dial "3625550100" on the cell phone. If you enter this code while in a vehicle, it will also repair it. Note: This phone number translates to "DOC-555-0100". This code prevents the "Cleaned The Mean Streets", "Finish Him", "One Man Army", and "Walk Free" achievements from being earned.

Full health, armor, and ammunition
Dial "4825550100" on the cell phone. If you enter this code while in a vehicle, it will also repair it. Note: This phone number translates to "GTA-555-0100". This code prevents the "Cleaned The Mean Streets" achievement from being earned.

Weapons tier 1
Dial "4865550100" on the cell phone. This will unlock the baseball bat, handgun, shotgun, MP5, M4, sniper rifle, RPG, and grenades. Note: This phone number translates to "GUN-555-0150". This code prevents the "Cleaned The Mean Streets" achievement from being earned.

Weapons tier 2
Dial "4865550150" on the cell phone. This will unlock the knife, Molotov cocktails, handgun, shotgun, Uzi, AK47, sniper rifle, and RPG. Note: This phone number translates to "GUN-555-0100". This code prevents the "Cleaned The Mean Streets" achievement from being earned.

Remove Niko's wanted level
Dial "2675550100" on the cell phone. Note: This phone number translates to "COP-555-0100". This code prevents the "One Man Army" and "Walk Free" achievements from being earned.

Add one star to Niko's wanted level
Dial "2675550150" on the cell phone. Note: This phone number translates to "COP-555-0150".

Spawn Annihilator police helicopter
Dial "3595550100" on the cell phone. The Annihilator is armed with rockets. Note: This phone number translates to "FLY-555-0100". This code prevents the "One Man Army" and "Walk Free" achievements from being earned.

Spawn Cognoscenti
Dial "2275550142" on the cell phone. Note: This phone number translates to "CAR-555-0142".

Spawn Comet
Dial "2275550175" on the cell phone. Note: This phone number translates to "CAR-555-0175".

Spawn FBI Buffalo
Dial "2275550100" on the cell phone. Note: This phone number translates to "CAR-555-0100".

Spawn Jetmax
Dial "9385550100" on the cell phone. Note: This phone number translates to "WET-555-0100".

Spawn NRG-900
Dial "6255550100" on the cell phone. Note: This phone number translates to "MBK-555-0100".

Spawn Sanchez
Dial "6255550150" on the cell phone. Note: This phone number translates to "MBK-555-0150".

Spawn SuperGT
Dial "2275550168" on the cell phone. Note: This phone number translates to "CAR-555-0168".

Spawn Turismo
Dial "2275550147" on the cell phone. Note: This phone number translates to "CAR-555-0147".

Change weather and brightness
Dial "4685550100" on the cell phone. Note: This phone number translates to "HOT-555-0100".

The following codes require "The Lost And Damned" bonus downloadable content:

Spawn Burrito
Dial "8265550150" on the cell phone.

Spawn Double T bike
Dial "2455550125" on the cell phone.

Spawn Hakuchou bike
Dial "2455550199" on the cell phone.

Spawn Hexer bike
Dial "2455550150" on the cell phone.

Spawn Innovation bike
Dial "2455550100" on the cell phone.

Spawn Slamvan
Dial "8265550100" on the cell phone.

The following codes require "The Ballad Of Gay Tony" bonus downloadable content:

Explosive sniper rifle shots
Dial "4865552526" on the cell phone.

Super punch
Dial "2765552666" on the cell phone.

Spawn Akuma bike
Dial "6255550200" on the cell phone.

Spawn APC
Dial "2725558265" on the cell phone.

Spawn Bullet GT
Dial "2275559666" on the cell phone.

Spawn Buzzard helicopter
Dial "3595552899" on the cell phone.

Spawn Floater boat
Dial "9385550150" on the cell phone.

Spawn parachute
Dial "3595557272" on the cell phone.

Spawn Vader bike
Dial "6255553273" on the cell phone.

Remove ammunition limit ("The Lost And Damned" DLC)
Get a 100% game completion in "The Lost And Damned" bonus downloadable content.

Bonus weapons ("The Lost And Damned" DLC)
Successfully complete the indicated task to unlock the corresponding weapon at your safehouse:

Assault shotgun: Successfully complete 40 gang wars and the "Heavy Toll" mission.
Automatic pistol: Successfully complete 20 gang wars.
Carbine rifle: Successfully complete 30 gang wars.
Grenade launcher: Successfully complete 50 gang wars.
Sawed-off shotgun: Successfully complete 10 gang wars.
Successfully complete the indicated task to make the corresponding weapon deliverable by Jim:

Automatic pistol: Successfully complete the "Bad Cop Drop" mission.
Pipe bombs: Successfully complete the "Hit The Pipe" mission.
Free guns ("The Lost And Damned" DLC)
Successfully complete all gang wars to get free guns from Terry.

Bati 801 bike ("The Lost And Damned" DLC)
Successfully complete ten bike thefts for Angus. The Bati 801 bike will now be available for Clay to transport to you or can be found parked near a safehouse.

Hokachu bike ("The Lost And Damned" DLC)
Win twelve races in single player mode. The Hokachu bike will now be available for Clay to transport to you or can be found parked near a safehouse.

Innovation bike ("The Lost And Damned" DLC)
Shoot all fifty seagulls. The Innovation bike will now be available for Clay to transport to you or can be found parked near a safehouse.

No ammo limit ("The Ballad Of Gay Tony" DLC)
Get a 100% game completion to remove the ammunition limit.

Bonus weapons ("The Ballad Of Gay Tony" DLC)
Successfully complete the indicated task to unlock the corresponding weapon at your safehouse:

.44 pistol: Successfully complete 10 Drug Wars.
Advanced MG: Successfully complete 20 Drug Wars.
Explosive shotgun: Successfully complete 30 Drug Wars.
Sticky bombs: Successfully complete 40 Drug Wars.
Gold SMG: Successfully complete 50 Drug Wars.
Gold Buzzard ("The Ballad Of Gay Tony" DLC)
Successfully complete the game to unlock the golden Buzzard at a heliport near the Booth Tunnel.

Gold Super Drop Diamond ("The Ballad Of Gay Tony" DLC)
Successfully complete the game to unlock the golden Super Drop Diamond outside Yusef's apartment.

Noose APC ("The Ballad Of Gay Tony" DLC)
Shoot all 50 seagulls to unlock the Noose APC at Henrique's construction site.

Parachute ("The Ballad Of Gay Tony" DLC)
Successfully complete all base jumps to unlock a parachute at your apartment.

Get any vehicle from any mission ("The Ballad Of Gay Tony" DLC)
During transport missions, there will be some cars, boats, and planes that can only be used in those missions. Simply kill the person that is with you in the vehicle to end the mission and keep the vehicle for use anytime.

Secret map locations
Go to a TW@ Internet Cafe, log into a computer, and enter "www.whattheydonotwantyoutoknow.com" as a URL to view maps that reveal all weapon, health, armor, vehicle, pigeon, ramp/stunt, and entertainment locations.

Unlockables
Successfully complete the indicated task to unlock the corresponding bonus:

Annihilator police helicopter: Collect all 200 pigeons (flying rats).

No ammo limit: Get a 100% completion.

Rastah Color Huntley SUV: Successfully complete 10 Package Delivery missions.

Special friendship bonuses
Reach the indicated level of friendship with the corresponding character to unlock their special friendship ability:

Alex (screen name "LiberatedWoman")

Method: Look for the personal ad from "LiberatedWoman" in the "Women seeking men" section of the "www.craplist.net" website. Alex is somewhat of a self-centered, spoiled rotten rich girl. She will compliment Niko for wearing expensive clothing and driving expensive cars. She will also write about her exploits with Niko in her blog at "www.blogsnobs.org". Reach 80% friendship with her.

Special ability: 50% off at all clothing stores.

Brucie

Method: Take him bowling, drinking, eating, strip clubs, shows, helicopter tours, and boating to reach 70% friendship.

Special ability (Chopper Ride): Call Brucie, and he will fly his helicopter to you. This allows you to fast travel to various portions of the city.

Carmen (screen name "SoboHoe")

Special ability (Health Boost): Restores Niko's health over the phone. She will call Niko every chance she gets.

Dwayne

Method: Take him to strip clubs, eating, drinking, shows, and bowling to reach 60% friendship.

Special ability (Extra Help): Call Dwayne to have a car full of gang members follow you.

Kiki (screen name "LawChick")

Method: Date LawChick via "www.love-meet.net" through the in-game internet. Take her out a few times to reach 75% friendship. When dropping her off, select the "Try your luck" option. Afterwards, she will call you and say she can clear the feds.