This study uses annual time series data on under five mortality rate for Sao Tome and Principe from 1965 to 2020 to predict future trends of U5MR over the period 2021 to 2030. Residuals and forecast evaluation criteria indicate that the applied ANN (12, 12, 1) model is stable in forecasting under five mortality rate. ANN model projections suggested that annual U5MR will hover around 17 deaths per 1000 live births throughout the out of sample period. Therefore, the government of Sao Tome and Principe should continue providing financial support to the maternal and child health program in order to keep under five mortality under control.