This study investigated the level of superstitious belief among 175 persons in three categories: persons undergoing inpatient psychiatric treatment, churchgoers, and college students. A 50-item inventory consisting of positive and negative common superstitions, including a 5-item invalidity subscale, was administered. Using a 2 (male, female) x 3 (patient, churchgoer, student) factorial design, analyses revealed significant differences among the three groups for total, positive, and negative superstition, with psychiatric inpatients having the highest, and church members having the lowest levels on all three. The findings support Ellis' theory that irrational beliefs impair realistic thinking and consequential functioning in everyday life. An explanation for the finding that psychiatric inpatients held the highest level of beliefs involves schedule-induced behavior, in which response is typically observed following reinforcement. The endorsement of superstitious beliefs by inpatients may also be seen as a defense mechanism. The results are also consistent with Schumaker's idea that nonreligious persons compensate for lack of identity with traditional religion by increased nonreligious paranormal beliefs. (Six pages of references, a table of superstitious beliefs administered to subjects, one data table, and three figures are included.) (Author/NB)