OBJECTIVES: Analyze and identify total time and cost of recruiting patients into a randomized clinical trials(RCT) of Motivational Interviewing-based behavioral interventions to enhance antiretroviral therapy(ART) adherence.  Despite numerous federally funded RCTs, little literature describes the cost of recruiting patients into behavioral interventions to enhance ART adherence. METHODS: A secondary data analysis of recruitment data collected for Project MOTIV8(R01 MH68197) was conducted. Data from 204 HIV+ patients recruited from the Kansas City metro area between June of 2004 and August of 2008 were examined for this cost analysis. Direct labor costs for all recruitment staff were collected. Microsoft® Excel spreadsheet was used to determine number of attempted recruits, average time spent to recruit/enroll a patient, number of successful enrollments, and project resources spent on recruitment.  Discounting and sensitivity analysis was done to determine the robustness of this cost analysis. RESULTS: Over four years Project MOTIV8 screened 1710 patients and successfully enrolled 204 participants(11.9%) into the study. The ratio of patients approached to successfully enroll was 8.38:1.  Ten minutes was the average time spent to recruit a patient, however it required 1.4 hours of effort to enroll an eligible patient in the study. All costs are reported in 2008 dollar value. The total cost associated with four staff members working on the recruitment effort came to $245,626.70(285 hours) over the study period.  The cost for attempted recruitment was $143.64(10 minute average) and the cost for successful enrollment was $1204.05(1.4 hours) for patients with HIV. CONCLUSIONS: The costs associated with recruiting participants into a study are often overlooked and underestimated. This economic analysis can serve as a guide to determine the budget for actively enrolling patients with specific risk behaviors. This data provides information for understanding ancillary costs and will help to shed light on unique challenges in the HIV business environment.