The inter-rater and test-retest reliabilities, and internal consistencies of the Reiss Screen for Maladaptive Behavior (Reiss 1987) were evaluated on a random sample of adults with moderate through profound mental retardation living in an institutional setting. Generally, the Reiss Screen showed good inter-rater reliability, modest to good test-retest and good internal consistency. This suggests that the Reiss Screen has moderate to good psychometric robustness.