Tenofovir-emtricitabine (TDF-FTC) has demonstrated effectiveness as HIV preexposure prophylaxis (PrEP), but it is not commonly prescribed. Our study was designed to determine the barriers preventing utilization of PrEP among men who have sex with men (MSM), the group at greatest risk for HIV infection in the United States. A population-based sample of MSM presenting for HIV testing at 'Early Test' HIV testing and counseling sites in San Diego, California were offered PrEP and education about potential efficacy. Eligible individuals reported having unprotected sex within the past 12 months and who tested negative for HIV were offered study participation. Despite offering procedures for evaluation and prescription for PrEP to 416 eligible subjects, less than 0.5 % of participants received the drug. Surveys collected from 54 of those who declined study participation revealed multiple barriers to PrEP among MSM including cost, low perceived risk of infection and concerns about taking a daily medication and potential long-term side effects. Efforts should be made to address these barriers, especially lowering the cost of TDF-FTC, education about PrEP side effects and awareness of HIV risks.