Treatment-resistant obsessive-compulsive disorder (OCD) patients from around the United Kingdom who employed computer-guided self-help by using BTSteps over 17 weeks were randomized to have brief live phone support from a clinician either (1) in nine Scheduled clinician-initiated calls or (2) only in calls Requested by the patient (n = 22 per condition). Call content and mean duration were similar across conditions. Scheduled-support patients dropped out significantly less often, did more homework of self-exposure and self-imposed ritual prevention (95% vs. 57%), and showed more improvement in OCD symptoms and disability. Mean total support time per patient over 17 weeks was 76 minutes for Scheduled and 16 minutes for Requested patients. Giving brief support proactively by phone enhanced OCD patients' completion of and improvement with computer-aided self-help. © 2005 Wiley Periodicals, Inc. J Clin Psychol 61: 1499–1508, 2005.