This study investigated the reliability and validity of the Norwegian version of the Automatic Thoughts Questionnaire. Three samples were used: (a) 344 male military recruits; (b) 142 psychiatric outpatients; and (c) 41 healthy controls. The Automatic Thoughts Questionnaire was found to have high internal consistency and satisfactory temporal stability. It correlated positively with the Beck Depression Inventory and was found to discriminate significantly between clinically depressed and non-depressed psychiatric patients and healthy controls. In general the results are satisfactory, suggesting that the Norwegian version of the Automatic Thoughts Questionnaire has adequate reliability and validity properties. The Automatic Thoughts Questionnaire was shown to be a useful measure of frequency of automatic negative thoughts in both clinical and non-clinical populations.