Roger Moore was Fleming's original choice to play 007, but he was under a network contract for the television show "The Saint". Other actors who were considered for the role of James Bond included Cary Grant, Trevor Howard, Rex Harrison and David Niven - he would play the role of Bond in the spoof 1967 film "Casino Royale".
The actor appearing in the gun barrel sequence at the beginning of the film is actually stunt man Bob Simmons. The same gun barrel with Simmons was used for the first three Bond movies.
In the scene in Dr No's apartments, Bond does a double-take at a painting displayed on an easel. It was in fact a copy of Goya's "The Duke of Wellington", the original of which had been stolen in a raid on a museum shortly before filming began. Producers thought that it would be interesting to conceive that "Dr No" himself had arranged for the real life theft.
Ian Fleming wanted his cousin Christopher Lee to play "Dr. No". Due to other projects, Lee had to turn the role down, but was later cast as "Scaramanga" in "The Man With The Golden Gun". Actor Max Von Sydow was also offered the part - he would later be cast as "Ernst Stavro Blofeld" in the non-Eon film "Never Say Never Again".