Amitabh Bachchan was offered to play the role of Mr India but he declined as he was into politics and was not doing many movies. Shekar Kapur wanted Anupam Kher to play the role of Mogambo but then switched to Amrish Puri as he wanted someone who looked scary.
When Prof. Sinha is first talking to his students in the class, on the blackboard behind him are displayed formulae from varied branches of science - mathematics, chemistry etc. Prominently visible is "Boney's Law of Time-Space Continuum". Boney Kapoor is the producer of the movie.
The film had originally been written for Rajesh Khanna in the lead role but he rejected it because he felt the "invisibility" factor was the main hero of the film. After some script changes by Shekar and Boney Kapoor, Anil Kapoor was cast in his place. Kishore Kumar sang the songs thinking it would be picturised on Rajesh Khanna and even Laxmikant Pyarelal were under the same impression.
In 1957, Nanabhai Bhatt made a movie with the title of "Mr. X" in which Ashok Kumar played the role of Mr. X and invisible man. This was the first Hindi movie to be made with a invisible man as the theme. Interestingly, Ashok Kumar who played the title role in the 1957 movie plays a supporting role as Professor Sinha in Mr. India.
When Dagga & Teja interrogate Ms.Hawa Hawaii and Mr. India shows up for the first time, Teja shoots 4 bullets out of the revolver before being slapped by Mr. India. Mr. India then shoots the chains of Hawa Hawaii with two bullets before pointing the (now empty) gun at the villains.
The sequel which was announced its plot was that it would be after 23 years where is Mr India and what happened to the invisibility formula,and a new terrorist arrives who wants to rule India and it was announced that Salman Khan would play the terrorist.
Before the film's shooting started, Aamir Khan begged Shekhar Kapur if he could be his assistant while directing the film. Satish Kaushik shot down the idea thinking Aamir Khan was too sophisticated and rich and would show up every day to the film's shooting in expensive cars . This theory of Aamir Khan would be proven wrong.
In 2008 Boney Kapoor announced a sequel to the film which was supposed to be comeback of Sridevi,Anil Kapoor and Sridevi would play the leads and Salman Khan would play character similar to Mogambo,AR Rahman was signed as the music director,the film is to be shot in 3D format but still the film hasn't gone on floors,technicians were said to be called from abroad to create Salman's look.