We assessed the incidence of drug abuse among patients requiring psychiatric hospitalization, and characterized the population at risk. The data on drug abuse were obtained from self-reports and urine tests in 103 patients, aged 18-65, hospitalized in the Kfar Shaul Psychiatric Hospital (autumn 1998). There was close correspondence between the self-reports and the results obtained from urine tests. 1/3 admitted to having used illegal drugs and signs of drug abuse were found in about 1/4 of the urine tests. The most prevalent drugs were cannabis products (hashish and/or marijuana) and in 15 patients opiates. Drug users were younger than non-users. With regard to psychiatric symptomatology, fewer negative symptoms were recorded among cannabis abusers with schizophrenia, compared to schizophrenic patients with no history, past or present, of cannabis abuse. The present findings confirm the clinical impression that there has been an increase in drug abuse among mental patients, parallel to that found in society at large. Confirmatory surveys are necessary. Our findings clearly suggest that a change in attitude has occurred in Israel to what has been considered a marginal problem. Hospitalized mentally-ill patients, the younger in particular, should be considered at risk for drug abuse.