On the staircases in most apartment blocks in the game, some graffiti pay homage to past protagonists set in GTA III canon (Claude, Tommy Vercetti, Carl Johnson, Toni Cipriani, and Victor Vance) in the form of scribblings of their names on the walls.

Binco from Grand Theft Auto: San Andreas was meant to appear in the game, but was replaced with the Russian Clothing Shop. You can see it in the "Looking For That Special Someone" trailer.

Judging from the audio file names, 'Tuff Gong Radio' was supposed to be called 'Babylon', and 'The Beat 102.7' was to be 'Beat 95'.

Niko Bellic, one of the game's protagonists, was based on the character Sasha from the 2001 film "Behind Enemy Lines" played by Vladimir Mashkov. Mashkov was even asked by Rockstar if he'd like to play Niko Bellic but, declined the offer.

The Dodo was at one point meant to appear in GTA IV. Some of the Dodo's handling data can still be found in the game's files.

When the player answers his cell phone while driving a bike, he uses his right hand. In reality, this would disable his ability to accelerate, as the throttle is located on that side; in the game, the player is somehow still able to operate and accelerate the bike while talking on the phone.

Despite appearing in Promotional Artworks and Early Screenshots, Nikos fingerless gloves are not found in-game. However, they are still in the game's data and can be obtained through mods.

Going to the website "Littlelacysurprisepageant.com" from a computer in-game will get you an automatic five-star wanted rating. The website's address is a reference to the Grand Theft Auto: Vice City Stories radio commercial "Little Lacy Surprise" featuring Jack Howitzer.

Inside the Statue of Happiness, behind a door with a sign saying "No Hidden Content this way", is a large beating heart.

In The Lost and Damned expansion, a car called Rhapsody can be found in Alderney and Bohan. The Rhapsody is based off of an AMC Pacer, the model driven by Wayne and Garth in the movie, Wayne's World. The car's name is a reference to the scene in which Wayne and Garth sing the Bohemian Rhapsody song in Wayne's World. The front of the Rhapsody features a 'W' for its badge, indicating Wayne's World, and on the inside of the car in a picture of Wayne and Garth.

The official artwork for Lola Del Rio (which was used to promote the game) shows her with six digits on one hand; five fingers and a thumb underneath.

Grand Theft Auto IV previously held the record for being the most expensive game to develop, coming in at $100 million. The record was previously held by Shenmue, at $47 million, and is now owned by Grand Theft Auto V

According to the Liberty City Police Department's database, Niko Bellic's first criminal offense was "Grand Theft Auto" in 2008, the same year that Grand Theft Auto IV was released.