BACKGROUND Addiction, in addition to social and economic problems, can cause serious oral health complications and impose huge costs of treatment and elimination of oral health problems among addicts. The present study was conducted to investigate DMFT and CPITN indices among drug users in Ilam's addiction treatment center. METHODS This is a cross-sectional study, conducted in Ilam's addiction treatment centers and all patients who visited the centers for drug rehabilitation for one month were closely examined and studied. Clinical examinations were performed by the dentist in order to evaluate DMFT and CPITN indices. The collected data was analysed by SPSS version 18. ANOVA and t-student were used to examine the individual information and oral indices. RESULTS Most of the patients were aged between 30 to 40 years and their mean age was 42.16±5.6; the youngest subject was 20 and the eldest was 77 years old, who were addicted to marijuana and opium. 197 (97.5%) male and 5 (2.5%) female subjects were studied. 130 patients (64.5%) were addicted to opium, 26 (12.8%) to heroine, 20 (9.9%), 11 (5.4%) to crack 15 (7.4%) were addicted to marijuana. 147 (73%) of addicts had dyspepsia and 98 (48.5%) had severe dental sensitivity. Temporomandibular joint disorders were observed in 84 (42%) patients; severe gingival bleeding was observed in 42 cases. The mean DMFT index turned out to be 15.8 in this study. Drug users in this study had an inappropriate oral and dental health status. CONCLUSIONS Proper oral health and preventive dental care interventions are strongly recommended in treatment centers.