Development In the early 1960s,
C. V. Sridhar founded the production company
Chithralaya. When discussing with his associates what should be the company's first film, Sridhar came up with the story of
Nenjil Or Aalayam; however, he later decided that the company's first film should not be a tragic one, and came up with the lighter
Thennilavu (1961). After that film's success,
Nenjil Or Aalayam was revived. Inspired by an American film starring
Mickey Rooney which was entirely set in prison, Sridhar decided to do a film set in a hospital. Sridhar initially planned a different plot line for this film with
Sivaji Ganesan as an old age character suffering from terminal disease, but since Sridhar was dissatisfied with this plot, he came up with a new plot.
Casting Sridhar strictly wanted newcomers/less prominent artistes to star.
Kalyan Kumar, though popular in
Kannada cinema, was a relative "stranger" to Tamil cinema, and was cast as the main character Murali. She accepted as she liked the story.
Nagesh stayed with actor
K. Balaji during his early days as an upcoming comedian for three years. Balaji introduced Nagesh to Sridhar, who offered him a role on Balaji's recommendation. Nagesh revealed that he was initially to play the role of a country bumpkin, but was chosen by Sridhar to play Peter, the hospital attendant. The screenplay and dialogues for Nagesh's portions were written by
Chitralaya Gopu.
Filming , but the close-up shot of the fingers playing the sitar were actually those of
Ahmed Hussain.
Principal photography took place entirely on a hospital set at
Chennai's
Vijaya Vauhini Studios. Ganga was the art director, N. M. Shankar was the editor, and
A. Vincent was the cinematographer. For the first scene, Nagesh was told to jump from the steps when Sridhar warned him not to do but Nagesh assured he will pull it off. After jumping, he was surprised to see Sridhar missing from the sets and this scene was instead directed by his assistant
P. Madhavan. Gopu then said he did this to make sure Nagesh should not feel scared to perform in front of Sridhar. The song "Sonnathu Neethaana" is picturised on Devika's character Seetha playing the
sitar, but the close-up shot of the fingers playing the sitar were actually those of
Ahmed Hussain.
Nenjil Or Aalayam was the first Tamil film to be shot entirely on a single set. Ramya Kannan of
The Hindu, and
Tamil Canadian journalist D. B. S. Jeyaraj state the completion time to be 22 and 28 days respectively. Malathi Rangarajan of
The Hindu said the film was completed in 25 days. The final length of the film's prints were long. == Music ==