In order to make an adequate basic dataset for a subsequent hydrological research, the study of interpolation of precipitation values from measurement stations (points) to large areas (areas) was done. Among many statistical interpolation methods that estimate precipitation values in unsampled areas (where there are no measurements or they are sparse), spatial interpolation method which includes relief (elevation) was chosen for the study. Inclusion of elevation parameter was done in order to minimize the extent of interpolation errors. Research was done in the catchments area of the Srkapež River (Western Serbia). Precipitation data were collected from 19 measurement stations for the period from 1961 to 2000. The reduction method was used for filling the missing data in the data set. The best framework for managing spatial (georeferred) data is Geographical Information System, enabling easier calculation and improved precision. Therefore, raster GIS was used for spatial interpolation of precipitation and for calculating mean annual precipitation value. Concerning the fact that the observed area is a mountainous region, where precipitation may change over short spatial scales, a DEM with a grid resolution of 100 m was used.