The efficacy of prolonged single sessions of live graded exposure (LGE) and computer-aided vicarious exposure (CAVE) for spider phobia was examined in a single-blind, controlled trial. Forty participants diagnosed with specific phobia (spiders) received a prolonged single-session treatment of either therapist-aided LGE comprising exposure only or CAVE, or were assigned to a waiting list. Phobic symptomatology was measured at pre- and post-treatment, and at 1-month follow-up on a range of behavioural and subjective assessments. The results showed that the single-session therapist-aided LGE was superior to both CAVE and the waiting-list control. In contrast with previous findings of comparability between LGE and CAVE, and superiority of CAVE over placebo, the present study found no significant differences between the CAVE and waiting-list groups, with the exception of subjective units of distress, providing little support for single-session CAVE treatment.