During the initiation of the final part of the companion quest "ED-E, My Love", a glitch could occur where Senior Knight Lorenzo's dialogue can be randomly replaced with a placeholder version of the voice line. This placeholder line was performed by producer and programmer Jason Fader, who was asked by area designer Akil Hooper to provide two very different temporary voice lines for ED-E's broadcasts of Lorenzo and April Martimer's voices. Fader performed Martimer's voice with an impression of the horror character Count Dracula, and performed Lorenzo's voice with an impression of Inigo Montoya from the 1987 film "The Princess Bride". Although these placeholder lines were removed from the final game, one line of Fader's Inigo Montoya impression could still be heard in-game if a certain flag in the game's code was tripped. Fader's father discovered the bug through gameplay footage on YouTube and brought it to his attention as he recognized Fader's "dumb voices". Fader recalled that commenters on the YouTube video shown to him flatteringly questioned why a Mexican voice actor was used for only one line in the game, oblivious to its origin.

A Vault Boy image named "perk_survivalist" appears in the game files. It differs in appearance from the original survivalist perk (found in Fallout, Fallout 2, and Fallout Tactics), and its unclear what it would do as it was never implemented into the game though it seems to imply that the perk was originally planned to appear in New Vegas.

With the Wild Wasteland perk activated, players can find the words "Romanes eunt domus" written on the side of a building in Cottonwood Cove. This is a reference to the Monty Python movie, "Life of Brian", in which Brian attempts to graffiti "Romans go home" on a building in Latin. However, the statement has several translation errors (much to the chagrin of a passing centurion) and literally translates to "People called Romanes they go the house."

Despite a higher resolution texture being available in the game's resources, the Spiked Knuckles used by the player do not use the high resolution texture.

Dennis Crocker was originally planned to be Caucasian, but his lines were voiced by a non-Caucasian voice actor so the developers changed the character's appearance accordingly.
His original design can still be seen on the collectors edition playing cards.

By using console commands during the ending slideshow it's possible to find a character called "Ron the Narrator", who is used to narrate the slides and other sections of the game.

He can be seen wearing Legion armour, and is based off the actual narrator, Ron Perlman.

There was originally an NCR super mutant ranger named Chauncey stationed at Station Foxtrot. he was included in early builds of the game, but ultimately cut prior to release.

The Feral Ghoul Roamer has an error when loaded into editing software. While this doesn't cause conflicts in the game itself, the model attempts to draw from a model labeled "mmm_ghoulvariant_v1.nif". This is one of the feral ghoul variants that appeared in the Fallout 3 mod Mart's Mutant Mod, suggesting that Obsidian Entertainment had experimented with it while developing new features for the game.

Obsidian's Scott Everts attributes some of the performance issues and simplifcation present in the game to the fact it wasn't a PC exclusive.

As a unique pre-order bonus at K-Mart, buyers received four coasters representing the four major casino found in the game, The Ultra-Luxe, Vault 21, The Tops, and the Lucky 38.

Matthew Perry was cast in Fallout: New Vegas due to being a fan of the previous game; Fallout 3. He also gave away a signed copy of Fallout 3, not because he was in it, but rather just because he claimed it was his favorite game.

A Wrecked Highwayman can be found half-submerged in mud and, upon finding it, one of two background songs from Fallout 2 ("My Chrysalis Highwayman" or "Gold Slouch") will play. The trunk is filled with Energy ammunition, making it a nod towards the Highwayman in Fallout 2, which used Energy ammo as a fuel source. The original idea for this encounter came from J.E. Sawyer, who originally planned it for the cancelled Van Buren game, which would have included the Tanker FOB in the trunk from Fallout 2.

If the player has the Wild Wasteland trait, and nukes both the NCR and Caesar's Legion at the end of the Lonesome Road DLC, the ending slide will Spoiler:quote Charlton Heston and show a picture representing the ending scene from the original Planet of the Apes.

In the "Dead Money" DLC, when entering the wine cellar near the bell tower from which the player triggers the Gala Event, the phrase "I AM NOT YOUR MUMMY" is scrawled on the central pillar. This is in reference to the Ghosts' gas masks and the two-part episode of Doctor Who, "The Empty Child and The Doctor Dances".

If the player chooses to arm Archimedes I and leave Fantastic alive, in the quest "That Lucky Old Sun", upon returning the player will find Fantastic wearing Legion armor and having just killed his co-worker, Ignacio Rivas, stating "Hey man, when in Rome."

A portrait of the mother and father of Fallout 3's protagonist, The Lone Wanderer, can be found in Vault 21, next to Sarah's bed.

The Child at Heart perk from Fallout 3 was set to return to New Vegas, but was ultimately cut, most likely because there are very few children in the game. Unused dialogue can still be found within the game's audio files, however.

The challenge "A Slave Obeys" requires the player to Spoiler:kill Mr. House with the 9 Iron or Nephi's Golf Driver. This is a reference to the original Bioshock, in which the player Spoiler:beats the game's main antagonist, Andrew Ryan, to death with a 9 iron while he repeats the words "A man chooses, a slave obeys."

The perk "In Shining Armor" doesn't actually do anything. The perk was supposed to give the player an additional +5 Damage Threshold against energy weapons while wearing any metal armor, and +2 while wearing reflective eyewear.

The perk doesn't provide any Damage Threshold boost due to the fact that the parameter that is referenced when checking the skill type of enemy weapons is "Energy" instead of "EnergyWeapons". This means that the function "IsWeaponSkillType" will never return a value that can activate the perk effect, because there is no weapon skill called "Energy".

Most of the Honest Hearts Tribals speak a creole language.

The Dead Horses' language is based on German, English, and Navajo, although the morphology of the Navajo is unrecognizable.

The White Legs speak a combination of languages from tourists and locals in a place called Res.

The Sorrows language seems to be a combination of broken English, German, Spanish, and hints of Japanese.