The aim of the study was to estimate the frequency of occurrence, a degree of intensity and time and space variability of atmospheric drought periods during vegetation season of plants determined on the basis of relative precipitation index (RPI) and hydrothermal index (K) in north-west Poland. The material was mean-monthly values of air temperature and monthly total precipitation for the vegetation season (from April to September) over 1965-2004 from 12 IMGW stations situated in Pomerania. Occurrence of drought in Pomerania is a phenomenon which is remarkably space-variable and it applies to all Pomerania. However, the area located in the south-west can be considered as the most threatened with drought, and the area situated in the north of Pomerania as the least threatened. In the centre and east part of Pomerania the month with the most frequent occurrence of drought of different severity according to RPI was April, and in the western part – it was July. In almost all Pomerania drought occurred the least frequently in August, only along the Baltic coast – in September. In 1965-2004 no statistically significant tendency of RPI index variability was recorded. The values of the K hydrothermal index showed a downward tendency in subsequent years in April and May, which was significant at the level α <0.1 in April – in the south and north of Pomerania, and only in the south – in May.