- Acting for Two: Tony Goldwyn as murderous twins Greg and Rick Knowles in "Doppelganger" and "Doppelganger, Part 2".
- Banned Episode: The Escape channel skips over the episode "Our Sons And Daughters" because of the graphic depiction of sex between teenagers.
- California Doubling: Set in New York City, filmed in Los Angeles, though they did travel to New York to film the exteriors.
- Channel Hop: The repeats have aired at various times on the Escape and Pop channels, sometimes only on one or the other and as of 2020, are airing on the Bounce channel, again at varying times.
- Directed by Cast Member: Eric Close (Martin Fitzgerald) directed a handful of episodes, as did Marianne Jean-Baptiste (Vivian Johnson).
- Executive Meddling: For its first four seasons, the show aired on Thursdays at 10 pm until September 2006 (it was the first show to put a dent in the ratings of ER, which was beginning its 9th season at the time WAT premiered). Then for the fifth season, it was moved to Sundays. For the sixth season, it was returned to its original Thursday timeslot, then moved again to Tuesdays at 10pm for it's seventh and final season.
- Fake American: Half the damn cast. Anthony LaPaglia (Jack Malone) and Poppy Montgomery (Samantha Spade) are Australians and Marianne Jean-Baptiste (Vivian Johnson) is British.
- Name's the Same: Martin Fitzgerald is also the name of a character on the Soap Opera Passions.
- Real-Life Relative: Poppy Montgomery had been dating Adam Kauffman for two years before he began a recurring role on the show as Samantha's baby daddy/ love interest Brian Donovan.
- Recycled Script:
- The episode "Lost Time" is virtually identical to Cold Case's "Hubris"—pretty college student who was having an affair with her professor, is presumed killed by him. The difference in this situation is that the teacher was convicted of her murder and spent 7 years in jail, while the weird classmate was the guilty one. In Cold Case, the roles were reversed.
- The Season 2 episode "Wannabe" and the Season 4 episode "Safe" both featured a bullied boy disappearing, with his tormentors being the prime suspects. Both boys are found at the end, two seconds away from killing themselves.
- Season 1's "Snatch Back" and Season 3's "Manhunt". A disturbed person who lost a child kidnaps one to replace them and is Driven to Suicide after being caught and forced to give them back—even the "please give the kid back speech" is virtually identical. The only difference is the gender (female in the first episode, male in the second) of the victim and the kidnapper and that in the latter episode, the agent is able to stop the guy from killing himself.
- Season 3's "Nickel And Dimed" is echoed in Season 5's "Candy"—struggling woman goes missing, it's linked to her dead-end job, female agent (Samantha and Elena, respectively) goes undercover in job and nearly gets killed themselves when they get close to the truth.
- There have been several episodes featuring the disappearance of pregnant women.
- Similarly Named Works: "Without A Trace" is also the name of a 1983 movie.
- Unintentional Period Piece:
- The pilot episode (which aired in the fall of 2002) mentions a suspect flying back to New York via the Concorde, which hasn't flown since 2003.
- Another Season 1 episode from the fall of 2002 has Martin and Jack making jokes about the Chicago White Sox, which at the time was in the midst of an 85-year World Series title drought, a losing streak that was finally broken in 2005.
- The agents are also often shown using some now-defunct technology, such as phone books and videotapes (do either of those even exist anymore?).
- Written by Cast Member: Anthony LaPaglia cowrote the episode "Deep Water".
- Written-In Infirmity: Poppy Montgomery's Real Life pregnancy resulted in Samantha Spade becoming a mom too.
Trivia / Without a Trace