Updated: July 28, 2025

Season 1 ( 1966 to 1967 )

NBC ordered 16 episodes of Star Trek, besides "Where No Man Has Gone Before". The first regular episode of Star Trek, "The Man Trap", aired on Thursday, September 8, 1966, from 8:30 to 9:30 as part of an NBC "sneak preview" block. Reviews were mixed; while The Philadelphia Inquirer and San Francisco Chronicle liked the new show, The New York Times and The Boston Globe were less favorable, and Variety predicted that it "won't work", calling it "an incredible and dreary mess of confusion and complexities". Debuting against mostly reruns, Star Trek easily won its time slot with a 40.6 share. The following week against new programming, however, the show fell to second ( 29.4 share ) behind CBS. It ranked 33rd ( Out of 94 programs ) over the next two weeks, then the following two episodes ranked 51st in the ratings.

I am an avid fan of Star Trek, and would simply die if it was taken off the air. In my opinion it is the best show on television.

Frederik Pohl, editor of Galaxy Science Fiction, wrote in February 1967 of his amazement that Star Trek's "regular shows were just as good" as the early episodes that won an award at Tricon in September. Believing that the show would soon be canceled because of low ratings, he lamented that it "made the mistake of appealing to a comparatively literate group", and urged readers to write letters to help save the show. Star Trek's first-season ratings would in earlier years likely have caused NBC to cancel the show. The network had pioneered research into viewers' demographic profiles in the early 1960s, however, and by 1967, it and other networks increasingly considered such data when making decisions; 115  for example, CBS temporarily canceled Gunsmoke that year because it had too many older and too few younger viewers. Although Roddenberry later claimed that NBC was unaware of Star Trek's favorable demographics, awareness of Star Trek's "quality" audience is what likely caused the network to retain the show after the first and second seasons. 115  NBC instead decided to order 10 more new episodes for the first season, and order a second season in March 1967. The network originally announced that the show would air at 7:30â€"8:30 pm Tuesday, but it was instead given an 8:30â€"9:30 pm Friday slot when the 1967 to 68 NBC schedule was released, making it less appealing to young adult viewers.