Original I Love Lucy episodes aired on Monday nights on CBS.
The series premiered on October 15, 1951, and its original 180 black-and-white half-hour episodes continued in the Monday-night schedule through May 6, 1957. That regular placement helped make the show a dependable weekly event during television's early network era.
The Monday schedule applies to the original I Love Lucy series, not every later program connected with the characters. After the six-season run, the format changed to occasional hour-long specials under titles including The Lucille Ball-Desi Arnaz Show and, in syndication, The Lucy–Desi Comedy Hour. Those later broadcasts did not follow the same weekly Monday pattern.
A related point of confusion is the unaired pilot. It was filmed before the series began and was not part of the original broadcast run; it was eventually shown decades later. The regular series itself is the one associated with Monday nights on CBS.