The later Charles Bind movie, Undercover Lover (1979), had a similar title to this Charles Vine movie's UK title of ''Licensed to Kill''.
Actor Tom Adams played Charles Vine in all three Charles Vine pictures: The 2nd Best Secret Agent in the Whole Wide World (1965), Where the Bullets Fly (1966) and O.K. Yevtushenko (1967).
The movie's theme song in the American version, ''The Second Best Secret Agent in the Whole Wide World'', is featured in the later John le Carré (2008) film drama Tinker Tailor Soldier Spy (2011). The track was composed by Sammy Cahn and Jimmy Van Heusen and performed by Sammy Davis Jr..
This James Bond imitation film was first released in the same 1965 year as the official James Bond movie Thunderball (1965).
The film in English language markets and territories is alternatively known as ''Licensed to Kill'' in the UK and ''The Second Best Secret Agent in the Whole Wide World'' in the USA.
Sammy Davis Jr.: Uncredited, in the American version, as a singer behind the film's opening credits.