- Actor Allusion: John Leyton, who guides Ryan through a series of trap doors and secret passages, also played Willie, one of the tunnel kings in The Great Escape.
- California Doubling: An Italian POW camp was recreated in California.
- Executive Meddling: The only reason the character of Gabriella is in the movie.
- Playing Against Type: This was the first role Frank Sinatra had that didn't ask him to sing.
- What Could Have Been: According to Saul David's memoirs, Frank Sinatra was desperate to have Richard Burton as his co-star. Sinatra was not aware, however, that 20th Century Fox, were in the middle of a bitter court case with Burton and Elizabeth Taylor over the massive cost overruns on Cleopatra, and wouldn't even entertain the thought of hiring Burton. Sinatra had made plenty of overtures to Burton in the hope he would sign on, and he was furious that he had wasted his time and effort.
Trivia / Von Ryan's Express