It is well established that many patients with obsessive-compulsive disorder have covert, or internal, compulsions. Empirical studies of this phenomenon, however, are limited. The present study followed the paradigm developed by Rachman and his colleagues for the study of overt compulsions. Patients with urges to carry out covert compulsions underwent an experimental procedure in which their compulsive urges were provoked, followed by a period of response prevention. The strength of the compulsive urges and associated discomfort were monitored. There was marked, and relatively rapid, spontaneous decay of both the compulsive urges and the discomfort. Implications of these results are discussed.