Unlike many other Bollywood productions, the filmmakers actually complied with international copyright laws and bought the license to the rights to Roy Orbison's "Pretty Woman" which is featured in the film.
The dolls and dollhouse that Gia plays with in the movie are slightly modified dolls from the Loving Family line by Fisher Price. The house is the Special Edition Townhouse version of the line's dollhouse. In particular, the doll that she uses as Aman, is actually the father doll that came with the house. Slight modifications include adding cloth coverings to the grandmother doll's head to look like a sari and adding a poncho to the mother doll to more resemble the kurti (tunic) that Jaya wears. The modifications and dresses were actually made by Preity Zinta the day before the shooting of the scene
In the hotel scene when Aman convince Jenifer to renovate her hotel and then they change its name from Cafe New york to Cafe New Delhi, when customers enter, Farah Khan and Karan Johar is also seen there sitting as a customer.
The film was originally going to be shot in Toronto but due to the SARS scare at the time, Karan Johar moved it to New York. However some parts of the song "Kuch To Hua Hai" in the movie are shot in Toronto.
Kal Ho Naa Ho also shares with the only other two Bollywood Films - Kabhie Kabhie (1976) and Saathiya (2004) to be the only Bollywood film that holds the maximum (3) number of music awards (where the title song is exactly the same with the film).