One of the main methods for the determination of death time, is to use the insects on the body. Because insects that comes onto the body immediately after death, take an active role of decaying the body.  Therefore, many insect species constitute a sequential structure on the carcass, in the process of the first to the final stage of decay. That’s why, It is vital to know the regional insect fauna to be used them for this purpose. Finally, the aim of this study is to identify the first stage forensic species of Diptera (Arthropoda: Insecta) in the province of Nevsehir. For this purpose, insect traps will be placed in the districts of Nevsehir which includes of four different direction (Kozaklı, Derinkuyu, Gülşehir, Ürgüp) and the central of the city. However, traps are designed as to allow easy ingress of insects, but not to escape of them. And also, fresh cow spleen was placed inside the traps. In addition, traps were allowed to stand in the field for a month and checked regularly. Besides, daily temperature data from weather stations were taken during the study. After one month, traps were opened and adult and larvae forms of blow flies (Diptera: Calliphoridae)  were collected. Then identification of these insects were made. As a result, the data obtained from this study, can be used to determine the time of death in the fatal incidents that occurred around Nevsehir city.