The validity of the Vocabulary Block Design subtest combination as an estimate of the WAIS-R [Wechsler Adult Intelligence Scale-Revised] full scale IQ in a sample of 30 psychiatric patients was investigated. The correlation between the short form IQ and the WAIS-R full scale IQ was highly significant (r(28) = 0.87, P < 0.001). A pairwise t-test computed between the mean IQ for the standard and short form was nonsignificant (t(29) < 1). Of the Ss [subjects], 1/2 showed changes in intelligence classification when the short form was used. The short form should not be used when precise IQ estimates are required. The short form appears useful as a screening device to discriminate between patients with normal and subnormal intelligence. With respect to the detection of normal vs. subnormal intelligence, the short form achieved a correct classification rate of 87%.