ABSTRACT Objective: to identify the social factors that determine the incidence of aids in the Piauí territory. Method: an ecological study that uses geoprocessing techniques in which 2,908 aids cases of individuals residing in Piauí were considered, notified to the Notifiable Disease Information System (Sistema de Informações de Agravos de Notificação, SINAN), from 2007 to 2015. Gross and Bayesian incidence rates were calculated using the population of the central year (2011), multiplied by 100,000 inhabitants, with Bayesian statistics used to identify spatial clusters. The non-spatial Ordinary Least Squares Estimation (OLS) and spatial Geographically Weighted Regression (GWR) regression models were used to identify the social determinants of the incidence of aids in the state, with 5% of significance. Results: the highest rates of the disease are concentrated in cities near the capital Teresina, with a Bayesian incidence of over 11.27 cases/100,000 inhabitants. The predictor variables of the incidence of ADIS in Piauí cities were the following: the percentage of individuals in houses with inadequate walls (p=0.0139), the mean number of residents per household (p=0.0309), and the percentage of individuals in households vulnerable to poverty and in which no one has completed elementary school (p=0.0051). Conclusion: according to GWR, the social factors that influence the incidence of aids in the cities of Piauí are the percentage of individuals in houses with inadequate walls, the mean number of residents per household, and the percentage of individuals in houses vulnerable to poverty and in which no one has completed elementary school. Given the above, interventions on the health social determinants of a structural nature should be established as effective methods for the prevention of HIV/ aids.