We derived and tested a short form of the Center for Epidemiologic Studies Depression Scale (CES-D) for reliability and validity among a sample of well older adults in a large Health Maintenance Organization. The 10-item screening questionnaire, the CESD-10, showed good predictive accuracy when compared to the full-length 20-item version of the CES-D (x = .97, P < .001). Cutoff scores for depressive symptoms were ≥16 for the full-length questionnaire and ≥10 for the 10-item version. We discuss other potential cutoff values. The CESD-10 showed an expected positive correlation with poorer health status scores (r = .37) and a strong negative correlation with positive affect (r = —.63). Retest correlations for the CESD-10 were comparable to those in other studies (r = .71). We administered the CESD-10 again after 12 months, and scores were stable with strong correlation of r — .59. (author abstract)