Many authors have questioned the validity of the major existing measures of self-actualization (the Personal Orientation Inventory, the Personal Orientation Dimensions, and the Short Index of Self-actualization), given their serious theoretical and methodological limitations. A new inventory was developed, the Measure of Actualization of Potential, and various studies were conducted to assess its theoretical and empirical content as well as its construct validity, internal consistency, and temporal reliability. The present aim was to estimate the criterion validity of the new measure using humanistic clinical psychologists' assessments as the criterion. The results show that eight clinical psychologists' rankings of 73 individuals are positively and highly correlated with the scores obtained by the same individuals on the Measure of Actualization of Potential.