To compare the efficacy of various psychometric tests in the detection of subclinical hepatic encephalopathy (SHE), cerebral functions were studied in 20 nonalcoholic cirrhotics without overt encephalopathy and in 18 matched healthy controls. Wechsler Adult Intelligence Scale (WAIS) indicated that verbal ability was preserved in all cirrhotics. Of the WAIS performance tests, block design test (BDT) was abnormal in 11 (55%), picture arrangement in 10 (50%), object assembly in eight (40%) and digit symbol in six (30%) patients. Taken together, these tests diagnosed SHE in 14 (70%) patients. Number connection test (NCT) alone, on the other hand, was abnormal in 13 (65%) patients. A combination of NCT and BDT yielded the diagnosis of SHE in 15 (75%) patients. An important measure of the reliability of the diagnosis of SHE was that NCT and BDT were independently abnormal in 10 of these patients. Both NCT and BDT were found easy and quick to administer. In conclusion, our results argue in favor of using a combination of NCT and BDT for a rapid and accurate diagnosis of SHE in patients with cirrhosis of the liver.