The authors studied the course of opiate dependence among two ethnic groups in Minnesota, one of whom used heroin by injection and one of whom used opium by smoking. Subjects were 57 Hmong (Laotian) immigrants and 80 native-born Americans. American subjects were more likely to be employed, had more education, younger age at onset of opiate use, higher addiction scores, more legal problems, spent about 50 times more money per day on drugs, had used more treatment, and more self-help methods. Hmong subjects were more men, more married and living with family, had longer periods of abstinence, and more of certain psychological symptoms. Differences were related to culture, type of opiate, and immigrant/refugee status. Similarities (e.g., types and severity of certain drug-related problems, family history of substance abuse) suggested that certain core features of opiate dependence persist despite differences in ethnicity and type of opiate used.