All 750 undergraduate students of the Medical College, Patiala, during the academic year 1976--1977 were covered in this survey. Seven out of ten students were found to have used some drug in the past. The lifetime prevalence being 82.4% among boys and 29.6% among girls. A majority of the students (78.6%) were poly-drug users, the commonest drugs used being alcohol (58%), tranquillizers (47%), and tobacco (36%). However, the prevalence of daily use was low, it being highest for cigarette smoking, by 9.4% of students, while less than 2% reported daily use of alcohol. The only other drugs used on a daily basis were stimulants (0.9%), tranquillizers (0.6%), and sedatives (0.3%). Of the opium users 81.8%, and over 60% of alcohol and tobacco users, had started taking these drugs during high school or the pre-medical year. On the other hand a majority of the students using tranquillizers (75%) and stimulants (66%) began using these drugs after entering the Medical College. The percentage of drug users increases by approximately 10% during each year of their medical studies.