The heritage of San rock art in southern Africa is globally acknowledged, and was one of the primary reasons for the successful nomination of the uKhahlamba / Drakensberg Park in South Africa as a World Heritage Site. Deterioration of rock paintings in the reserve could adversely affect the international status of the region, particularly as little has been achieved with regard to preserving the art for future generations. A study is currently under way in the Injisuthi and Giant's Castle areas of the park, to investigate the deterioration of San art; this article serves to introduce the project and to highlight some initial findings. Previous research on the weathering of San paintings has focused largely on either monitoring rock shelters or investigating rock surfaces that are adjacent to the paintings. None of the methods applied in earlier investigations has considered the interface between rock and pigments, mainly because of the potential damage that may result from the use of tactile monitoring equipment. Recent advances in weathering research, using improved techniques to measure conditions at the rock surface where the San art is painted, provide new insights into surficial processes and suggest new lines of investigation.