Rainfall data for the Netherlands have been used in this study to investigate aspects of heterogeneity of rainfall, in particular local differences in rainfall levels, time trends in rainfall, and local differences in rainfall trend. The possible effect of urbanization and industrialization on the distribution of rainfall has also been studied. Consideration has been given to whether local differences in rainfall justify a partition of the Netherlands into regions. Finally, the degree of areal reduction which is possible in hydrological design because of variation of rainfall in time and space has been investigated.A statistical analysis of these aspects is useful because they frequently appear in the hydrological literature. The statistical analysis presented in this thesis uses hydrological concepts, such as the statistical areal reduction factor, and attention is focused on moderately low return period events. Only rainfall levels and trends in rainfall have been investigated and not more complicated aspects, such as, trends in the variance of rainfall. Further, rainfall variations in time and space have been analysed separately.Estimates of the levels of the rainfall characteristics used in the investigation of homogeneity in time and space are given in Section 2.2. These are annual frequencies of exceedance during the summer or the winter period of a certain threshold value and the total annual rainfall (Tables 2.1 and 2.2). The expected daily rainfall has also been estimated for return periods in excess of half a year (Table 2.4, Figure 2.2). Time trends in rainfall averaged over the Netherlands have been estimated. For the period 1951-1979, the time trend is negative for the summer period; and for the period 1906-1979, the time trend is positive for the winter period (Table 2.5). Time trends in rainfall series were found to be related to the occurrence of circulation types (Figure 2.4).In Section 2.4 local differences in these rainfall characteristics have been investigated using the kriging method that ...