Food preferences of giraffe have been extensively investigated but few data concerning the chemical composition of the preferred species are available. The present study was aimed at ascertaining whether the differences in chemical composition of leaves of preferred food plants influence food selection. Furthermore, whether there are differences in the chemical composition of the specific plant species utilized at different localities and to provide information on the nutritive value of indigenous trees. Availability of the 54 preferred plant species studied was also considered. Moreover the seasonal utilization of the plants and its relation to their chemical composition was evaluated by a nonparametrical statistical method. The crude protein of the leaves of Acacia spp. is generally higher than in those of other species and they are therefore a better food source than e.g. Combretum spp. The leaves of preferred plants show the following seasonal trends: a decrease in moisture and protein content from January until August/September when they again increase; conversely, the two carbohydrate fractions, crude fibre and nitrogen-free extract, increase during the corresponding period until August/September, whereafter they decrease again. Variations in the ether extract and ash fractions show few or no trends. Leaf moisture content was always greater during the night than during the day. This may be important for supplementing water gain in times of drought.