Forensic entomology is a branch of forensic science that uses information about behavior and life cycle of insects that can serve as evidence. Moreover, that information refers to human, plant and animal life. The most important task of the forensic entomologist is to determine the post mortem interval, that is: the time of death. However, it is necessary to approach post mortem intervals calculation with caution, as there are factors such as the physical characteristics of the corpse, different types of flies and ecological factors which make it more difficult to determine the exact time of death. The aim of this paper is to examine whether there is a difference in the number and diversity of species of necrophagous types of flies in the Split area. Furthermore, that diversity is the result of various environmental conditions, especially plant composition on the micro location. The presence of different species of flies as a result of the environmental conditions prevailing in those locations will be tested on two different locations in the city of Split. In order to determine whether there are differences in the number of species and diversity, a 4-day study will be conducted. It is necessary to create protein traps for which plastic bottles will be used. A bait is placed inside of each trap, and the bait in this research will be chicken liver. At the bottom of the bottle it is necessary to pour a solution of alcohol and formalin for the purpose of stifling the flies and preventing their decomposition. In the end, the collected samples will be prepared and identified. Dichotomic identification keys are used for identification. The results demonstrated the existence of higher number of different species of flies at the site located in Marjan Forest Park. Two locations are not far from each other, so it can be concluded that differences in numbers and diversity is caused by ecological factors. Ecological factors of the utmost importance are exposure to sunlight and the composition of vegetation. Larger number of same species and higher diversity have been proved at the Marjan Forest Park location, and conditions that dominate there are denser vegetation and shaded conditions.