Starring: Dick Van Dyke, Mary Tyler Moore, Morey Amsterdam, Larry Mathews, Rose Marie
Three Letters from One Wife - S4-E10
Factual error: Millie mails 14 letters to Alan Brady with names of dead relatives, and to give them different postmarks she says that she drove all over Westchester and southern Connecticut to mail them. The next day, all 14 have arrived. Mail crossing a state line would not likely have made it overnight.
Your Home Sweet Home is My Home Sweet Home - S4-E25
Continuity mistake: The Petrie house (where Rob and Laura, Jerry and Millie are standing together bickering) is completely different from the episode "Where Did I Come From?" and a few others.
Rob Petrie: At least I'll prove one thing tonight: Television writers marry the prettiest girls.
Harrison B. Harding of Camp Crowder, Mo. - S1-E6
Trivia: Rob tells the police over the phone "Get a prowl car to 148 Bonny Medow Road." 148 was also Dick Van Dyke's weight during the TV series.