Background: In forensic entomology, a way to estimate Post Mortem Interval (PMI) is to use development data of the first colonizing insects on a dead body. Chrysomya albiceps and Calliphora vicina, two members of the family Calliphoridae, are the first waves of necrophagous insects that are the most entomologically important fly species because of its consistent time of arrival and colonization of the body following death. Regarding the bioclimatic, environmental conditions and difference in geographic population, it seems necessary to collect data about the forensically important species in each region. In this research, the growth rate of immature stages of C. albiceps and C.vicina was studied in controlled laboratory conditions. Results: The results of this study showed that with increasing temperature, the duration of development was reduced. The highest period of development, for both species, is related to pupae stage and involves about half of the entire development period. The amount of Accumulated Degree Days (ADD) for the egg stage to mature of the species C. vicina, at two temperatures of 15°C and 20°C, are calculated as 416 and 396 DD, respectively. Conclusion: This study showed, temperature had significant effects on rate of the development on Chrysomya albiceps and Calliphora vicina and the amount of heat energy needed to development for these species is specific. Actually, the relationship between the development rate and temperature was significant and dependent to species and geographical regions.
