This study examined successional patterns, relative abundance of larvae and adults of sarcosaprophagous insects, carcass decay, diversity and seasonality of species, and their potential as forensic indicators. Four experiments were carried out in each season in a natural area of southeastern Brazil. Two pigs were used in each experiment and were exposed to sunlight and shade, respectively. The Calliphoridae outnumbered the Sarcophagidae in specimens collected and reared from the carcasses. More insects were collected from carcasses exposed to the sun, while a larger number of specimens were reared from those in the shade. Temperature and rainfall influenced the stages of carcass decay, insect activity, and abundance. Chrysomya albiceps was the most abundant species in all four experiments. The carcasses were used as a protein source and substratum for oviposition. The dark putrefaction and fermentation stages yielded more flies than the other stages. These results show that flies are important in carcass decay and are, therefore, also of forensic importance. The study considers seven species to be valuable forensic indicators in Southeastern Brazil. However, only three species were useful as forensic indicators in wooded areas. Tables, figures, references