Chrysomya megacephala (Fabricius) and Chrysomya rufifacies (Macquart) are two important species of blow flies that could be utilised as indicators to estimate the Post Mortem Interval (PMI) of corpses in forensic science. Determination of PMI of corpses is based on the larva size and its development stages. Development studies of eggs, larvae and pupae of Ch. megacephala and Ch. rufifacies at 27ºC, 30ºC and 33ºC were carried out using an insect growth chamber. Data from these studies were used to construct growth curves and Accumulated Degree Hours (ADH) for both species. Ch. megacephala needs 9.15 days to complete one life cycle at 27ºC, 8.54 days at 30ºC and 6.76 days at 33ºC. Development for Ch. rufifacies is slower than Ch. megacephala and takes 9.92 day at 27ºC, 9.13 days at 30ºC and 7.44 days at 33ºC. Eggs of the two species hatch faster at 33ºC compared to the two other temperatures. Low value of ADH shows shorter life cycle of that particular species. This study’s findings are useful in estimating PMI of the corpses found under various environmental temperatures.