The fluoride content of snow was determined at various distances from a mixed fertilizer factory in Siilinjärvi, central Finland. Elevated fluoride levels were observed at less than 2 km from the factory, and the highest concentrations close to the factory were about 600 g of fluoride per liter of melt water. At unpolluted reference sites the fluoride content was about 6g/1. The background level of fluoride in precipitation is discussed. An ion selective electrode and a simple calibration method were used in the analyses.