Filming started on January 9, 1961. Filming took two months, with studio work at the Production Centre, location work at Poughkeepsie and exteriors shot at Vassar Brothers Hospital. Many of the cast were taken from the New York stage. Filmed in New York City's Women's Hospital, Manhattan General Hospital, and St. Luke's Hospital; and Vassar Brothers Hospital, Poughkeepsie, New York. Technical advisor Charles F. Begg, M.D., was Director of Laboratories at St. Luke's Hospital.
Although shot in academy 1.37:1 aspect ratio (for later television airing) the theatrical -- or *intended* (by the studio, producer, director and/or cinematographer) -- aspect ratio of this film is 1.85:1 widescreen. Most modern 16x9 (1.77:1) televisions have a "zoom to width" picture option, essentially allowing the viewer to see the film as the director and cinematographer originally planned. It is easy to spot films shot this way since all the titles and credits will still fit when properly cropped (they stay in the "middle" of the frame vertically), and there is an unusual amount of "headroom" above the actors in medium and close-up shots when viewed uncropped. Quite often "mistakes" -- like seeing equipment in the top or bottom of the uncropped frame -- would never have been seen by a theater audience.
Los médicos jóvenes (1961) was based on the source novel The Final Diagnosis by Arthur Hailey (Garden City, New York, 1959).