Surface water is a significant indicator of anthropogenic load and its quality depends on the content of sulphate, the most important acid component of atmospheric deposition. Samples of streams were collected in the Malá Fatra National Park (NPMF) and its protective zone. Sulphate showed the highest concentration of surface water acidic ions. Their concentration in the streams varied from 13.9 mg 1-1 (Biela) to 43.6 mg 1-1 (Istebnianka). Stream location in NPMF was found to be an important factor. In southern exposition areas the mean concentration of sulphate was found to be 21.1 mg 1-1 whereas the highest one was found in western and eastern expositions, to 30 mg 1-1. This suggests an influence from long-range transport pollution (the Czech Republic, Poland) and pollution from local industrial regions (Kovohuty Istebné).