This study was conducted from March 2006 to 2007. The aim of the study was to determine the forensically significant Calliphoridae (Diptera) species and their seasonal distribution in Ankara province at Beytepe Campus. Pig carcasses were killed by a veterinary using pentobarbital sodium with intervals from 2 to 3 weeks to a month. Samples were collected from the carcass everyday in the morning, in the afternoon, and at sunset. Temperature and parameters of weather, such as cloudy, sunny, rainy, and snowy, were recorded at each visit. Phaenicia sericata (Meigen), Chrysomya albiceps (Wiedemann), Calliphora vomitoria (Linnaeus), and Calliphora vicina (Robineau-Desvoidy) species, which belong to Calliphoridae family, were collected. It was shown that the seasonal distribution of the collected species was different from each other. The species were determined on carcass between the following times; P. sericata, from April to November; C. albiceps, from May to November; Ca. vomitoria, from February to June and from September to December; and Ca. vicina, from February to May and in June and September. Calliphoridae fauna and its annual seasonal distribution in Turkey on 12 pig carcasses were reported for the first time in this study.