This study presents data on the sensitivity to change of the Padua Inventory-Revised (PI-R), the Yale Brown Obsessive Compulsive Scale (Y-BOCS), and the Anxiety Discomfort Scale (ADS) for obsessive-compulsive disorder. In a sample of obsessive-compulsives (n = 63) who received either behaviour therapy, cognitive therapy, or a combination of fluvoxamine and cognitive therapy or behaviour therapy, evidence was found for the sensitivity of these three measures. However, low correlations were found at pretreatment, and only moderate correlations on percentage difference score. These findings indicate that different measures assess relatively different features of the OCD. All three measures demonstrated highly significant treatment effects and large effect sizes. Although the PI-R, the Y-BOCS, and the ADS showed clinically significant changes, there was only a small overlap (57%) on this index. The ADS is the most sensitive treatment outcome measure. It is recommended to use all three measures in outcome studies of OCD.