Here we studied the the diet and habitat use of buffalo (Syncerus caffer caffer) on Doornkloof Nature Reserve (DNR) in the Nama-Karoo, South Africa. The buffalo were predominantly grazers. Only seven grass species formed the bulk of their diet and marked seasonal shifts were observed in the contribution of these species to the diet of buffalo. Eragrostis lehmanniana and Sporobolus fimbriatus formed most of the food eaten in the wet seasons but contributed little to the diet in the dry season. By contrast, T. triandra contributed little to the diet in the wet seasons but formed the bulk of the diet in the dry season. This pattern appears to be related to the distribution of and to the seasonal changes in the acceptability of these grass species to buffalo. In the wet seasons the buffalo mainly foraged in the lowland habitats adjacent to riverine thickets containing E. lehmanniana and S. fimbriatus which were favoured by buffalo at this time. This pattern changed in the dry season when the buffalo ranged further from the cover of the riverine thicket and moved through the lowland habitats into the upland habitats where Themeda triandra, which was favoured in the dry season, was abundant. The favourable nitrogen and phosphorus concentrations recorded in buffalo feacal samples on DNR suggests that buffalo are likely to perform well in this environment and the population growth appears to confirm this.