The hygrothermal properties of starch filled polypropylene (PP) composites with different types of starches; sago, tapioca, and corn content at 20 wt% were studied. The PP composites were compounded using Brabender Plasticoder machine and the composites samples were prepared through by compression molding technique. The hygrothermal absorption test was conducted out to investigate the moisture absorption at different temperatures (i.e. room temperature, 40°C and 70°C). Thus, the flexural test was carried out to study the effect of hygrothermal conditions on mechanical properties and scanning electron microscopy (SEM) used to verify the obtained results through morphological study. The results revealed that the mechanical properties of PP composites deteriorate after a period of immersion time and the hygrothermal aging of composites was accelerated as the temperature increased.