OBJECTIVES: To analyse the association between socio-economic status (SES) and HIV in Manhica, a district of Southern Mozambique with one of the highest HIV prevalences in the world. METHODS: Data were gathered from two cross-sectional surveys performed in 2010 and 2012 among 1511 adults and from the household census of the district's population. Fractional polynomial logit models were used to analyse the association between HIV and SES, controlling for age and sex and taking into account the nonlinearity of covariates. The inequality of the distribution of HIV infection with regard to SES was computed through a concentration index. RESULTS: Fourth and fifth wealth quintiles, the least poor, were associated with a reduced probability of HIV infection compared to the first quintile (OR = 0.595, P-value = 0.009 and OR = 0.474, P-value