Approximately 33% of China is karstic. The most extensive karst areas are in southwestern China and cover approximate­ly 540,000 km2. Southwestern China hosts some of the most typical karst landforms in the world and has important high-quality karst water resources. Due to the rapid development of China, karst waters are threatened by various types of con­tamination. Detail field and laboratory investigations in five provinces including several cities in southwestern China were conducted in 2008 and 2009. Eighty-three springs and under­ground rivers were surveyed and water samples collected from eachfor laboratory analyses for major ions. Four main types of karst aquifer contamination were identified based on con­taminant sources: rural and agricultural pollution, pollution from urban development and industry, pollution from mining, and accidental groundwater pollution. Several representative instances for eachtype of contamination and their impacts on the environment are discussed in more detail. Contamination countermeasures of karst waters and a framework for overall management of karst water resources in southwestern China are provided.