Research was conducted to determine the purposes of closed circuit television ("CCTV") surveillance in prison. Despite the significant financial investments in CCTV and apparent satisfaction with performance, few studies have explored why CCTV is in prison. Research conducted in community settings suggests that the purposes of CCTV are prevention, detection, improving safety, gathering evidence, and acting as a general site management tool. Content analysis of legislation and procedure, physical audits of prisons (n=4), and interviews with managers (n=4) were conducted to determine why CCTV was in prison. Overall, the findings suggested that CCTV was in prison as a means of detecting and/or preventing highly specific behaviours (such as contraband entering prison, self-harm or suicide, and escape), as a means of identification for remote access control, and to facilitate the co-ordination of responses to incidents, gather evidence, and improve safety.