A vision screening program was established at a regional center for individuals with severe or profound mental retardation. The visual acuity measure used was the acuity card procedure, a type of forced-choice preferential looking. Acuity values were evaluated in terms of test-retest reliability as well as inter- and intraobserver reliability. Acuity results compared favorably to those obtained in less compromised populations, and we conclude that the acuity card procedure is a useful screening tool for this population. Suggestions for its application in evaluating functional vision were also discussed.