The present study describes the experiences and results of the first 5-year period of a municipal dental clinic offering free dental care to drug addicts. One of the many problems was the instability of this socially deprived group whose erratic life style made it impossible to maintain regular dental care. The DMFS level of the drug addicts was 50.2 and mean caries increment per yr was 2.5 (1.3 new surfaces and 1.2 surfaces with recurrent decay). The caries increments among the present drug abusers and the individuals on methadone maintenance were higher than among the previous drug addicts, 3.1 and 1.3 surfaces per yr respectively, but this difference was not statistically significant. Only slight improvement in oral hygiene (VPI) could be demonstrated whereas gingivitis (BI) remained unaltered. Traumatic injuries of the orofacial region were frequent. The mean time expenditure concerning dental treatment was 5 hr per individual in the initial treatment phase but decreased to 1-2 h per individual per yr. Broken appointments and last minute cancellations were as a rule related to drug/alcohol abuse. The mean number of fillings was 8.2 per individual in the initial treatment phase and 1.7 per yr for individuals in a maintenance phase. The poor dental health of the drug addicts seems closely related to their life style habits and the clue to an improvement would probably follow the cure of the drug abuse and a concurrent resocialization.