This master's thesis is historical demography study, based on data form Bizeljsko parish registers. The basis of this thesis is a combination of statistical methods and literature analysis. The goal is to obtain as objective picture of demographic developments in parish of Bizeljsko throughout the 19th century. The parish registers of Bizeljsko were selected as primary source, within which we examined in more detail all three main events recorded by these books. The goal of this thesis is to expose demographic developments at the parish level and to find historical causes and factors that helped to shape this development. Our findings are then placed in broader Slovenian context and compared with similar studies that touches the Slovenian territory.