The thesis discusses demographic characteristics of Split-Kaštela Zagora, and the data were processed by using Microsoft Office Excel and ArcGIS. Thesis provides a preview of historical events from the 16th century to 1971 in political, administrative, social, economic and demographic terms. Also, the circumstances of the development of the Split-Kaštela Zagora and the population trends have been presented. The focus of the research was on a more detailed analysis of population from 1971. to 2011. Population trends, age and gender structure, natural population change and migration, aging and the deagrarization of population were analyzed. From the analysis of demographic data it is evident that the number of inhabitants of the Split-Kaštela Zagora was increasing from the first population census in 1857 until 1931, and from that time on, it has been decreasing constantly. Today, the population of this area is aged, age and sex structure is unfavorable, and the share of the population engaged in agriculture is below the national average.