The South African Demographic Health Survey data set (SADHS) contains massive individual-level information on South African children under the age of five years selected from a random sample of 7, 759 households. The data set contains data on socio-economic, demographic, health-related and sanitary variables gathered by using multi-stage cluster sampling. The objective of study was to identify key predictors of mortality among children under the age of five years. Survey logistic regression analysis and Cox regression were used for performing data analysis. Under-five mortality was significantly influenced by 3 predictor variables (duration of breastfeeding, marital status, and ownership of flush toilet). The hazard ratio of the variable breastfeeding was 3.09 with P=0.000 and 95% confidence interval of (1.899, 5.033). The hazard ratio of the variable toilet was 2.35 with P=0.016 and 95% confidence interval of (1.172, 4.707). The hazard ratio of the variable marital status was 1.74 with P=0.035 and 95% confidence interval of (1.041, 2.912). Adjustment was done for th