In this paper, the results of measurements of radon (²²²Rn) in the drinking water of Dehradun City are presented. The radon was measured in water samples taken from the tube wells and hand pumps which are the usual sources of water supply in the city. The recorded radon concentrations in 19 water samples from different hand pumps were found to vary from 27 to 154 Bq·l^–1 with an average of 67 Bq·l^–1, while radon concentrations in 49 water samples from different tube wells were found to vary from 26 to 129 Bq·l^–1 with an average of 59 Bq·l^–1. The results are compared with international recommendations for human exposure. These recorded values were found to be above the average of the recommendations but well below the highest recommended value of 400 Bq·l^–1. In general, the drinking water of Dehradun city is contaminated by radon at a concentration which is reasonably uniform over the study area.