The different collected insect species were distributed on the carcasses according to the decomposition stages or postmortem intervals (PMI). In the winter season, the insect succession showed that carcasses placed outdoor attracted the greatest numbers and highest diversity of insect species. The calliphorid fly; Chrysomya albiceps was first attracted to the bloated and decay stages. In both habitats (outdoor and indoor), the numbers and diversity of insect species on carcasses were decreased during the advanced decay stage and then increased again during the dry stage. In the spring season, Chrysomya albiceps was the first fly attracted to the fresh or bloated stage of dog carcass in both habitats. Moreover, calliphorid flies were disappeared during the advanced decay stage in both habitats. While Coleopteran insects appeared during the decay and advanced decay stages. In the summer season, the forensic insect species showed nearly the same distribution of the different decomposition stages. Also, Chrysomya albiceps was the first fly attracted to the early stages of decomposition. In general, it appeared that the diversity and numbers of forensic insect species, which colonize dog carcass, were increased outdoor and decreased indoor. In the autumn season, carcasses placed outdoor attracted the greater numbers and higher diversity of forensic insects. The calliphorid fly, Chrysomya albiceps,and housefly, Musca domestica were first attracted to the fresh and bloated stages, especially of carcasses placed outdoor. The adult beetles, Dermestes maculatus, Necrobia rufipes and Hister sp.were early seen during bloated, decay and advanced decay stages.