BACKGROUND: Although the burden of impaired renal function is rising in sub-Saharan Africa (SSA), little is known about correlates of impaired renal function in the region. We determined factors associated with estimated glomerular filtration rate (eGFR) and impaired renal function in HIV-infected and HIV-uninfected adults. METHODS: We undertook cross-sectional analysis of data from 1947 adults at enrolment for a cohort study on diabetes and associated complications in HIV patients in Mwanza, north-western Tanzania. A structured questionnaire was used to collect data on sociodemography, smoking, alcohol, physical activity, antiretroviral therapy (ART) and anthropometry. We measured blood pressure, tested blood samples for creatinine, glucose and HIV, and performed Kato Katz for Schistosoma mansoni. Correlates of eGFR (mL/min/1.73 m2) and impaired renal function (eGFR< 60 mL/min/1.73 m2) were determined using linear regression and logistic regression, respectively. RESULTS: 655 (34%) participants were HIV-uninfected, 956 (49%) were ART-naive HIV-infected and 336 (17%) were HIV-infected adults on ART. The mean age was 41 years (SD12) and majority (59%) were females. Overall, the mean eGFR was 113.6 mL/min/1.73 m2 but 111.2 mL/min/1.73 m2 in HIV-uninfected, 109.7 mL/min/1.73 m2 in ART-naive HIV-infected and 129.5 mL/min/1.73 m2 in HIV-infected ART-experienced adults, and respective prevalence of impaired renal function was 7.0, 5.7, 8.1 and 6.3%. Correlates of lower eGFR were increasing age, higher socioeconomic status, unhealthy alcohol drinking, higher body mass index and diabetes mellitus. Anaemia was associated with 1.9 (95% Confidence Interval (CI):1.2, 2.7, p = 0.001) higher odds of impaired renal function compared to no anaemia and this effect was modified by HIV status (p value 0.02 for interaction). CONCLUSION: Impaired renal function is prevalent in this middle-aged study population. Interventions for prevention of impaired renal function are needed in the study population with special focus in HIV-infected adults and those with high socioeconomic status. Interventions targeting modifiable risk factors such as alcohol and weight reduction are warranted.