OBJECTIVES: To explore the risk factors for, and clinical outcomes in men who have sex with men (MSM) prescribed HIV postexposure prophylaxis following sexual exposure (PEPSE) at sexual health clinics (SHCs) in England. METHODS: National STI surveillance data were extracted from the genitourinary medicine clinic activity dataset (GUMCADv2) for 2011-2014. Quarterly and annual trends in the number of episodes where PEPSE was prescribed were analysed by gender and sexual risk. Risk factors associated with being prescribed PEPSE among MSM attendees were explored using univariable and multivariable logistic regression. Subsequent HIV acquisition from 4 months after initiating PEPSE was assessed using multivariable Cox proportional hazards models, stratified by clinical risk profiles. RESULTS: During 2011-2014, there were 24 004 episodes where PEPSE was prescribed at SHCs, of which 69% were to MSM. The number of episodes where PEPSE was prescribed to MSM increased from 2383 in 2011 to 5944 in 2014, and from 1384 to 2226 for heterosexual men and women. 15% of MSM attendees received two or more courses of PEPSE. Compared with MSM attendees not prescribed PEPSE, MSM prescribed PEPSE were significantly more likely to have been diagnosed with a bacterial STI in the previous 12 months (adjusted OR (95% CI)-gonorrhoea: 11.6 (10.5 to 12.8); chlamydia: 5.02 (4.46 to 5.67); syphilis: 2.25 (1.73 to 2.93)), and were more likely to subsequently acquire HIV (adjusted HR (aHR) (95% CI)-single PEPSE course: 2.54 (2.19 to 2.96); two or more PEPSE courses: aHR (95% CI) 4.80 (3.69 to 6.25)). The probability of HIV diagnosis was highest in MSM prescribed PEPSE who had also been diagnosed with a bacterial STI in the previous 12 months (aHR (95% CI): 6.61 (5.19 to 8.42)). CONCLUSIONS: MSM prescribed PEPSE are at high risk of subsequent HIV acquisition and our data show further risk stratification by clinical and PEPSE prescribing history is possible, which might inform clinical practice and HIV prevention initiatives in MSM.