Abstract The karstic aquifers of South Africa are an important source of water for many towns, rural areas and farms in parts of South Africa's Gauteng Province. Despite this no scientifically based designation of areas where potentially polluting activities could constitute a risk to groundwater resources and abstractions exists. Recent local research into groundwater vulnerability methods did not consider the unique properties of karst aquifers, and the need for a karst groundwater vulnerability mapping method was identified. The proposed VUKA method for karst groundwater vulnerability mapping in South Africa is an adaptation of the COP groundwater vulnerability mapping method. Modifications were necessary to adapt the original COP method to South African karst terrains. The new method was successfully used to assess the groundwater vulnerability at the Cradle of Humankind World Heritage Site in South Africa. The new approach may be used by South African land-use planners to investigate the suitability of dolomitic areas for development from a groundwater protection perspective, as is currently done with respect to dolomite stability (sinkholes and subsidence).