According to a 29 Jun 1966 DV news story, Roger Corman began work on The St. Valentine’s Day Massacre for Twentieth Century-Fox Film Corp. immediately after ending a contractual relationship with Columbia Pictures over “artistic differences” on A Time for Killing (1967 see entry). Scripting began in late 1965, as indicated by an 8 Dec 1965 Var article listing sixteen Fox projects currently in development. The 31 Aug 1966 Var reported a ten-week shooting schedule and $2.5 million budget, which was markedly higher than many of Corman’s other films at that time.
       Although Corman reportedly expressed interest in casting Marlon Brando as legendary Chicago, IL, gangster “Al Capone,” the role went to Jason Robards. Items in the 12 Jul 1966 and 1 Nov 1966 DV claimed that Jack Kelly, Lana Wood, and Mary Michael were also considered to appear.
       Principal photography began 24 Oct 1966, as stated in a DV production chart published four days later. According to an 8 Nov 1966 LAT story, filming took place on Stage 8 of the Fox studio lot in Los Angeles, CA, since Chicago proved unsuitable for the period setting due to the presence of modern street fixtures. Machine gun effects were achieved using circuit-laced striker boards; the 21 Dec 1966 DV estimated that “dummy” ammunition costs exceeded $9,000 for 10,000 bullets (priced at fifty cents apiece) and 20,000 explosive squibs (twenty cents apiece) to simulate wounds on the actors.
       Roles were supposedly allocated to six-year-old Brian Rapp, son of associate producer Paul Rapp, and four-year-old Laura Barry, son of assistant director Wesley E. Barry.
       The world premiere was scheduled for 30 Jun 1967 at the B&K Roosevelt Theatre in Chicago, as Var announced two days earlier. The citywide Los Angeles engagement began 12 Jul 1967, with New York City dates to begin at the Warner Theatre two weeks later, on 26 Jul 1967.