- Doctor Who - The Monthly Adventures (Big Finish Productions Limited UK)
- 275 total number
- United Kingdom (Maidenhead, United Kingdom)
The longest running science fiction audio play series consists of 275 instalments, and was achieved by Big Finish Productions Limited UK (UK) with Doctor Who - The Monthly Adventures, as verified on 20 April 2021.
The series began in July 1999 with The sirens of time.