We describe changes in sexual behaviors among men who have sex with men (MSM) following initiation of pre-exposure prophylaxis (PrEP) in a clinic-based sample of MSM initiating PrEP in Providence, Rhode Island. Data were collected at baseline, 3, and 6months following PrEP initiation including total number of anal sex partners and condom use. A longitudinal mixed effects model assessed changes in number of partners and condom use over time, adjusting for age, race, and education. There was no statistically significant difference in total number of partners over time. There was a significant increase in number of condomless anal sex partners at the 6-month visit compared to baseline (mean change +1.31 partners, 95% confidence interval 0.09-2.53, P=0.035). As condomless anal sex may increase following PrEP uptake, adherence counseling and efforts to retain patients in PrEP care, especially during periods of non-condom use, are important as PrEP is more widely implemented.