Two studies were conducted respectively to examine the reliability and validity of the standard Zung Self-rating Depression Scale (SDS), and a 10-item shorter version of the same test. In particular, the scale's usefulness as a screening instrument for depression among the Hong Kong Chinese elderly was investigated. In addition to the SDS, the Geriatric Depression Scale and the Chinese Hamilton Depression Scale were used to assess the convergent validity of the SDS. Data were collected from 113 nondepressed community-dwelling and 80 depressed elderly subjects. The findings showed that both the original and the shorter version of the SDS were highly reliable and valid. Both versions were appropriate for use as screening instruments for geriatric depression in Hong Kong. When compared with the original scale, the shorter version appeared to be slightly superior in its sensitivity and specificity in discriminating between the depressed and nondepressed subjects.