Consequent to the ICD-10, schizophrenic patients with illness duration of less than one month will now be diagnosed as acute and transient psychosis. On the basis of the hospital records of 891 first admission patients, the acute schizophrenic patients (n=253) were compared on demographic and clinical characteristics with the rest of the patients (n = 548) under 295 of the ICD-9 diagnosis. Logistic discriminant function analysis on 21 variables achieved 88% overall correct classification rate, 86% for short duration group and 89% for long duration group. Vie significance of the results is discussed.