The main purpose of the paper is to compare the water regimes of the watercourses in the upper course of the Lika River basin. The Lika is a sinking river in south-western Croatia on the Lika plateau, with its surface course flowing through the Ličko polje field. The analysis was made for the following hydrological gauging stations: Bilaj – Lika, Barlete – Jadova and Lički Novi – Novčica. The monthly and annual data series was analysed based on the available data on discharges in the 1964-1991 period. The basic characteristics of the analysed region are presented: the geographical position of the Lika River with climatic, hydro-geological and other characteristics of the area. The paper includes the characteristic statistical indicators of the analysed series, intra-annual distribution of characteristic mean monthly (maximum, mean and minimum) and monthly discharges. A course trend of the characteristic mean annual discharge values is analysed, a probability analysis of the occurrence of the annual discharge quantities is made, as well as a homogeneity analysis of the gauging stations, an analysis of the mean values of annual series, and an analysis of the frequency and duration of daily discharge data. Based on the analyses made it is identified that the data from all the three gauging stations is homogeneous, and that there is a clear decreasing trend of characteristic monthly and annual discharge values. It is also identified that there is high intra-annual variability in discharges, the reason for this being the torrential character of the Lika River and its tributaries in the upper part of its course.