['To investigate semen quality in HIV patients under stable antiretroviral therapy (ART) compared with WHO 2010 reference values and on the sperm proteome level.', 'Between 2011 and 2013, we prospectively enrolled 116 HIV-positive men without hepatitis B or C co-infections from our outpatient department for infectious diseases.', 'Patients received a comprehensive andrological work-up. Complete semen analysis was performed according to WHO 2010 recommendations, with each semen variable of the study population being compared with the WHO reference group (n~2000). Correlation analysis was done to investigate the influence of HIV surrogate parameters on semen quality. Two-dimensional gel electrophoresis and subsequent protein identification was performed to determine any differences in the sperm protein composition of the 15 HIV-positive patients and that of 15 age-matched healthy men.', 'Median values of all assessed semen parameters were within a normal range. However, for each semen variable, about 25% of patients had values below the fifth percentile of the WHO 2010 reference group. Disease-related parameters (CD4þ cell count, viral load, CDC stage, duration of disease, duration of ART, number and type of antiretroviral drugs) were not significantly correlated with any sperm parameter. Sperm proteome analysis identified 14 downregulated proteins associated with sperm motility and fertility.'] Is semen quality in HIV patients under stable antiretroviral therapy impaired compared to WHO 2010 reference values and on sperm proteome level?