The Organic Brain Syndrome (OBS) and the Depression (D) scales derived from the Comprehensive Assessment and Referral Evaluation (CARE) were translated into Italian and used in a survey of geriatric institutions in Milan. During the survey validity and reliability tests of the scales were conducted. Inter-rater reliability (total score weighted kappa) was highly satisfactory for both scales (0.96 for OBS and 0.83 for D scale). Reliability was assessed three times during the survey and showed good stability for both scales, with a slight but significant trend towards reduction over time for the D scale. Reliability of the D scale was significantly lower when the subjects interviewed scored highly on the OBS scale (severe cognitive impairment). Criterion validity was highly satisfactory both for the OBS scale (cut-off point 4/5: sensitivity 77%, specificity 96%, positive predictive value 91%) and the D scale (cut-off point 10/11: sensitivity 95%, specificity 92%, positive predictive value 84%). Results are discussed with special reference to longitudinal assessment of reliability, the choice of the cut-off point, and the context-dependent properties of questionnaires.