The aim of the present study was to investigate the nutritional status of drug addicts, the prevalence of malnutrition among them and the influence of their drug habit and lifestyle factors on their nutritional indices. The study was conducted among 253 male drug addicts, who sought detoxification at the Central Drug Addiction Treatment Hospital, Dhaka, during the period of June 1998–July 1999. One hundred age-, height- and socioeconomic-matched non-addicted healthy men were recruited by convenience as cohort controls. Results showed that the drug addicts had significantly (P<0·001) lowered BMI, haemoglobin, and serum total protein and albumin levels. Clinical signs of nutrient deficiency were diagnosed in about 74 % of drug addicts. The BMI, biochemical values and nutrient deficiency signs indicated that more than 60 % of drug addicts were suffering from multiple malnutrition. One-way ANOVA demonstrated a significant (P<0·05) negative correlation between drug habit, sexually transmitted diseases and selected nutritional indices, and a positive correlation between education, income and the nutritional indices. A series of multiple regression analyses revealed that education, income and age showed significantly predicted BMI and biochemical indices, and the group (non-drug addicts or drug addicts) had a significant negative effect on these parameters in favour of controls.