M.Sc. / This study aimed to systematically record and thus preserve indigenous plant use information of the Agter-Hantam area in a scientifically accurate way and to make a contribution to the knowledge of Khoi-San ethnobotany. The research work met all the minimum standards for ethnobotanical research as proposed by Heinrich et al. (2009), which includes that field studies should be built on a clear conceptual framework and hypothesis testing, that ethical clearance should be obtained, the methodology/ research procedures should adhere to minimum requirements, and the research should comply with data standards that will make it possible to use specific information in future experimental and applied research. The study area was the Agter-Hantam region, Calvinia district, Northern Cape Province of South Africa, where the ancestors of the supervisor have had a well-recorded presence since the 1770’s. The rapid appraisal methodology was initially used and this was followed by a new rigorous and practical quantitative approach developed during this study ̶ here referred to as the Matrix Method in conducting ethnobotanical field work. The survey has revealed a wealth of traditional knowledge on useful plants amongst people of Khoi-San decent in the Agter-Hantam. The traditional and contemporary uses of 64 plant species were accurately recorded. Previously unpublished information on indigenous plant use revealed by this study includes 14 new species records of useful plants, 20 new vernacular names not recorded in literature, and 99 new uses for 46 of the plant species. Although some work has been done in what Prance et al. (1987) coined as “quantitative ethnobotany”, this study also introduced two new terms- the Ethnobotanical Knowledge Index (EKI), a quantitative measure of a person’s knowledge of local plant use (with a value between 0 and 1), and the Species Popularity Index (SPI), a quantitative measure of the popularity of each species (value between 0 and 1). In the Agter-Hantam, the EKI of participants varied from 0.20 to 0.93. The best known and most popular indigenous plants in the Agter-Hantam are Aloe microstigma (a new species record, with a SPI of 0.97), Hoodia gordonii (SPI = 0.94), Microloma sagittatum (0.94), Sutherlandia frutescens (0.92), Quaqua incarnata (0.92) and Galenia africana (0.85).