Child mortality re?ects a country’s level of socio-economic development and quality of life. In developing countries, mortality rates are not only in?uenced by socioeconomic, demographic and health variables but they also vary considerably across regions and districts. In this paper, we analyze child mortality in Nigeria with ?exible geoadditive survival models. This class of models allows to measure smallarea district-speci?c spatial e?ects simultaneously with possibly nonlinear or timevarying e?ects of other factors. Inference is fully Bayesian and uses recent Markov chain Monte Carlo (MCMC) simulation. The application is based on the 1999 Nigeria Demographic and Health Survey. Our method assesses e?ects at a high level of temporal and spatial resolution not available with traditional parametric models.