These are the late night schedules for the four United States broadcast networks that offer programming during this time period, from September 1989 to August 1990. All times are Eastern or Pacific. Affiliates will fill non-network schedule with local, syndicated, or paid programming. Affiliates also have the option to preempt or delay network programming at their discretion. Legend Schedule Monday-Friday The Pat Sajak Show was reduced to 60 minutes on October 30, 1989. Saturday Sunday By network ABC Returning series Nightline New series Into the Night Starring Rick Dees CBS Returning series CBS Late Night CBS News Nightwatch The Pat Sajak Show NBC Returning series Friday Night Videos The George Michael Sports Machine Late Night with David Letterman Later With Bob Costas Saturday Night Live The Tonight Show Starring Johnny Carson Fox Returning series Comic Strip Live United States late night network television schedules 1989 in American television 1990 in American television