This paper details the process of genealogical research based on data from church records and the process of building a family tree. It also analyses data for several lines of the family tree which are then compared among themselves and to known demographic trends for their area. The aim of the paper is to provide a methodological background for genealogical research and point to the significance of such a research for acquiring a wider picture of everyday life in certain areas - living conditions, occupations or trades people went into and regional differences in age and time of marriage, conception, birth and death. During this research, data was gathered on the families Jelić and Šimunović from the village of Tisovac, Damjanović from the village of Vrbova, Ruškan from the village of Drežnik, Žagar from the small town of Prezid, Karlavaris from the town of Kastav and Ulrich which originated from Vransko in Slovenia and moved to the city of Rijeka in the 1880s. The presented statistical data for seasonal variations of marriages, births and deaths for each of the lines of the family tree greatly corresponds to demographic trends of the area they inhabited.