Goof (continuity error): In the episode "Case of the Crying Comedian", actress Sue Ane Langdon is seen sitting at the bar, then she comes down the stairs and moments later is seen sitting at the bar again.
Goof (revealing mistake): In "Case of the Grinning Gorilla", you can see the flesh underneath the eyes of the actor portraying the gorilla, especially in the close-ups.
Goof (revealing mistake): When Mason introduces the "newspaper photo" as evidence, since it shows great detail and no halftone dot pattern, it is obviously not from a printed paper, but is an actual photograph.
Goof (revealing mistake): When Mrs. Adams is found dead of a heart attack, the actress playing her is obviously still breathing.
Goof (continuity error): The district attorney introduces himself to Mason as Darwin Hale, but later in his office, Betsy Burris calls him Bill Hale.
Goof (boom mic visible): The shadow of a boom mike can be seen on the wall behind the judge's box during the last ten minutes of the episode.
Goof (continuity error): The left gauge on the oxygen tanks indicates "10" when the doctor examines it, yet it indicates "2" before and after his verification.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): At one point in Perry's office the real Louise refers to Myrna as Louise.
Goof (revealing mistake): Perry and Della spend the night in the lower level of a boat, supposedly alone. But when Della climbs the ladder to the deck to leave the boat, with Perry still waiting below, you can clearly hear her say softly to someone above "Excuse me."
Goof (continuity error): When Perry and Paul are at the Mexican Restaurant, after Nina gets up to handle a customer the candle disappears from the table.
Goof (continuity error): A janitor opens the door from the outside, he is not wearing glasses. The scene from inside the room shows the janitor now wearing glasses.
Goof (crew or equipment visible): Perry enters his office from the hallway door that Paul usually uses. As he's closing the door behind him, a hand outside the door can be clearly seen reaching for the doorknob to either close it the rest of the way or hold it closed.
Goof (continuity error): Color of unmarked police car tailing Perry Mason's car changes color from dark to light repeatedly.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): As Arlene listens to the radio, the announcer erroneously states that police are searching for the murderer of Frank Ballard rather than of George Ballard.
Goof (revealing mistake): Harry Pitkin is still breathing after he has supposedly been shot dead.
Goof (crew or equipment visible): (at around 30 mins) As Perry and Paul Drake enter a hallway and approach a hotel room door, just before looking through a transom window, a part of the sound-man's rig is clearly visible at the bottom right for 15 seconds.
Goof (revealing mistake): Claire Olger describes the dark-haired man who gives her a ride as having blonde hair.
Goof (revealing mistake): The newspaper story of the Greeley murder has text below the headline which is irrelevant to the murder. Also, the victim's name is spelled "Greely", not the spelling used in the credits.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): Harriet Bain refers to her father's continuing heart condition as "acute"; the correct word is "chronic".
Goof (plot holes): Dave Kirby describes having steel implants as a result of reconstructive surgery. Yet after a fatal plane crash, his corpse is confused with that of Dr. Morris, who presumably had no such steel implants.
Goof (revealing mistake): Art Williams photographed a murder scene from a small boat. The camera angle shows the picture to have been taken from the shore.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): Dr. Barnes's first name in the closing credits is listed as George and Mason uses the name George once. However, in court, Hamilton Burger refers to him as Dr. Philip Barnes.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): The same character Tony Davis, is called Anthony Davis in court by Hamilton Burger, and when Hamilton tells Lt. Arthur Tragg to pick him up for perjury he calls him Tony Davidson.
Goof (revealing mistake): The body rolled off the pier is obviously a stunt double wearing a skinhead wig.
Goof (errors made by characters, possibly deliberate errors by the filmmakers): In an atmosphere of spit-and-polish, squared away soldiering, an army officer says something happened at "10:15 p.m." instead of "22:15 hours".
Goof (continuity error): The Corregidor money that shows up at the beginning is identified by its serial number and is unburned. Mr. Blake from the Treasury Department states that all of the stolen money that has been appearing in circulation never got near the bonfire that was used to burn $10 million before the Japanese Army invaded. But by the time the trial starts, the stolen Corregidor money is now identified by being scorched on its edges implying that it was raked out of the fire before it could be burned.
Goof (factual errors): The MP captain testified that the typist using the defendant's typewriter was a touch typist because of the equally strong key indentations left on the typewriter ribbon. This is untrue; a touch typist leaves fainter indentations with the outer keys because he is typing with his little fingers.
Goof (errors in geography): The preliminary hearing is in Sierra City, County of Sierra, California. Both the town and the county are real, but the County Courthouse is in the county seat, Downieville.
Goof (continuity error): Witness Luke Hickey's testimony is interrupted so Lt. Tragg can take the stand because he is wanted at headquarters and has to leave. When Tragg is done he does not leave the courtroom and is seen sitting there through the rest of the scene.
Goof (factual errors): The murder victim is found in his office at the start of business hours, his shirt wet with blood. It is later established that he died between midnight and 2 am, so any blood on his clothing would long since have clotted.