Bhardwaj bought the original script of Kaminey for US$4,000 from Kenyan writer Cajetan Boy—whom he had mentored at a scriptwriting workshop in Uganda, later collaborating with screenwriters Sabrina Dhawan, Abhishek Chaubey and Supratik Sen to modify it.

The film's soundtrack album, composed by Bhardwaj, also became a commercial success, with the song "Dhan Te Nan" topping the charts on various platforms.

Charlie likes to take shortcuts to fulfill his dream of becoming a bookmaker at the racecourse, where he works for three criminal brothers who fix races.

The ensuing chase leads to the hotel car park, where Lobo and Lele are placing the guitar case in their van.

Bhope and Tashi negotiate to trade the drugs, but Charlie snatches the guitar case and threatens to destroy it if Guddu and Sweety are not released.

During a scriptwriting workshop held by Mira Nair in 2005,[9] Cajetan Boy, a Kenyan writer from Nairobi, showed Vishal Bhardwaj a script about twin brothers from the city's slums and the events that occur in their lives during a 24-hour period.

[11] Dhawan said that the film's script was complex and has multiple stories which required excessive writing and rewriting to make each character sound distinct.

[12] According to Bhardwaj, the idea for the title came from a scene from Gulzar's Ijaazat (1987), in which the lead actor (Naseeruddin Shah) refers to the actress in a loving manner; it was the first time that he heard the word used that way.

He stated, "A man named Honey introduced himself as Vishal Bhardwaj's casting director and offered me a very important role.

[16] The actors Chandan Roy Sanyal, Shiv Subramnayam, Hrishikesh Joshi, Rajatava Dutta and Deb Mukherjee were cast in supporting roles.

[17] For the role of drug dealer Tashi, Bhardwaj chose his friend Tenzing Nima—a tour operator in Mussoorie—saying he had the character and attitude he wanted, and a weird sense of humour.

[14] Bhardwaj instructed the film's entire cast and crew to watch caper classics such as Lock, Stock and Two Smoking Barrels (1998), Snatch (2000), Pulp Fiction (1994) and True Romance (1993) to study the nuances and become familiar with the genre.

The producers did not want them to look like caricatures, so Kapoor prepared for both roles by meeting and interacting with speech therapists and people with these impediments.

[7] Subramnayam and Joshi, who played Lobo and Lele respectively, described their characters as the most corrupt policemen in their department at the Anti-Narcotics Bureau.

[7] Dutta, who played Shumon—a Bengali criminal involved in fixing horse races and arms dealing—said that he did not have much time to prepare for his role because he was given the script after he arrived in Mumbai, where Bhardwaj briefed him.

[26] During filming, Chopra became hoarse because she had to scream her lines; an essential part of her role as an "extremely vocal Maharashtrian girl.

"[30] Unlike other Hindi films, in which the female lead is Sita, the protagonist is Rama and the antagonist is Ravana, the characters in Kaminey are nuanced humans in "layered and complex" situations.

[30] Namrata Joshi from Outlook wrote that Kaminey reflects Bhardwaj's "enduring fascination for underdogs, characters on the margins of society and the morally compromised".

Bhardwaj gave the twins verbal impediments to show that the world has now been so hardwired to convoluted and calamitous communication that it needs silence or a speech defect to hash things out.

"[30] A review in The Times of India said that the film's climax reaches the level of Reservoir Dogs, and described it as "absolutely riveting stuff, with the camera going on a hitherto unexplored journey in Indian cinema.

[41] The trailer, which introduces four characters; one lisping, one stuttering, a woman yelling about having raped a man and one jeering at the lisper, received positive reviews.

[42] Critics kept their expectations high due to Bhardwaj's previous films, and said the trailer was like a comic book which introduces the characters of Kapoor and Chopra differently.

[49] Moser Baer Home Videos released Kaminey on DVD in October 2009 across all regions in a two-disc pack complying with the NTSC format.

[52] The satellite rights for Kaminey were syndicated between Star India & Viacom 18 before being internalized by the former in 2020, and a world television première of the film was broadcast on Colors on 28 February 2010.

He also said, "Its lyrics are the blow-up-your-brains-out kind ... and its music, composed by the multi-talented Bharadwaj is perfectly in sync with a narrative that doesn't pause for breath.

"[59] Namrata Joshi from Outlook gave a rating of 4 out 5 and called Kaminey "a strikingly anarchic, unusually energetic, quirky and frenetic film".

[60] Sudhish Kamath of The Hindu gave the film 4 stars and wrote, "Kaminey takes the post-postmodern noir genre to a whole new level, to a sophistication the Indian audience isn't used to.

"[61][62] Writing for Variety, critic Joe Leydon described the film as a "tasty cinematic masala that is energetically entertaining, if not consistently coherent".

[82] Kaminey has received several awards and nominations in categories ranging from recognition of the film itself, to its cinematography, direction, screenplay, music and cast performances.

[85] It received eleven nominations at the 5th Apsara Film & Television Producers Guild Award and won two, one of which was Best Actress for Chopra.