A three-year (1991–93) study on atmospheric precipitation (bulk and throughfall) and stream chemistry was carried out in two — granitic (Waksmundzka Val.) and calcareous (Mietusia) valleys (Polish Tatra Mountains). It was found that both valleys were under acid rain influence — chemical analysis showed strong seasonal fluctuations of the studied elements. Chemistry of precipitation was dominated by sulphate ions, buffered more efficiently in Mietusia Val. than Waksmundzka Val. mainly by calcium and ammonium ions. In both valleys an increase of throughfall acidity compared to bulk precipitation was observed. There were also found differences between bulk and throughfall chemistry — amounts of hydrogen, calcium, potassium and ammonium ions in throughfall were higher whereas amounts of phosphate, copper and zinc ions were lower in throughfall than in bulk precipitation. In both valleys significant seasonal variation of most of the studied elements in bulk and throughfall was detected.