Entomology is the science that studies insects and forensic entomology examines insects found on dead bodies. Accurate identification of fly species is an important step in forensic entomology, given the fact that an insect collected on a carcass can provide useful information for estimating postmortem interval (PMI) i.e. estimating the time when death most likely occurred. The objectives of this master thesis are to collect, identify and determine the number and diversity of carnivorous species of flies and compare them between two cities – Split and Omiš. Also, the goal was to establish the influence of temperature, humidity and precipitation on the differences in the number and diversity of species. The protein trap for catching flies was made out of a plastic bottle with a hole cut in the middle through which the flies would enter, and at the bottom of the bottle we poured 70% alcohol. At the top of the cap on the inside of the bottle we hung the bait, fresh meat (chicken liver), and as such we hungit with a rope for a tree branch. The survey lasted three months (April, May and June), during three days and five weeks apart. Using the protein trap, a total of 366 individuals belonging to the order Diptera were collected, later identified in five families and nine species. The most numerous family was Calliphoridae (buzzard flies) with 6 identified different species, while the second most numerous was Psychodidae, whose species could not be identified, the third was Sarcophagidae (butcher flies) with 3 different species, followed by Anthomyidae with 2 and Phoridae with 1 unit that we also failed to identify. At the end of the research, we found that families and species differ in both number and diversity of species, inluding between the two studied areas and between the months in the same area. The differences are due to the influence of air temperature, humidity and precipitation in these locations and due to the diversity of the environment. Moreover, an additional factor that influenced their mutual number and diversity lies in the fact that the two areas are different per se. The location in the city of Split is located near the highway with a small number of trees, while on the other hand the area of location in Omiš is rich in pine forests and is characterized by untouched nature and considerable distance from civilization.