Background: Substance abuse has significant impact on nutritional status. Due to the increased malnutrition during drug use and withdrawal, this study aimed at assessing the anthropometric indices in individuals referring to drug treatment centers in Qom. Methods: In this descriptive-analytical study, 329 addicted individuals referring to addiction centers in Qom were randomly selected. A questionnaire was used with three parts including demographic characteristics, drug abuse history, and anthropometric indices including measurement of height, weight, waist circumference, arm circumference, and skinfold thickness in triceps and calf muscles. Results: The participants consisted of 328 men and only one woman, 29% of whom were in detoxification. The participants' mean age was 39.0 ± 7.1 years. The first and most-frequently used drug was opium. All anthropometric indices were associated with the consumption of opium substances and drug use was associated significantly with some parameters. With the exception of skinfold thickness in the calf, all the indices were affected by the type of consumed substances. The opium addicts had a higher body mass index compared with other drug users. Conclusions: Due to the importance of nutrition status in drug abusers' health and their lack of self-care, careful monitoring and evaluation of dietary intake, as well as nutrition status can play important roles in the rehabilitation of these individuals and help to prevent from reappearance of these habits.