The aim of this study was to investigate the serum immunoglobulins and white blood cells status of drug addicts and to assess the extent of influence of drug habit and sexual practice on the immune components. The study was conducted among 253 male drug addicts and 100 non-addict controls of aged 18 - 45 years. An enzyme-linked immunosorbent assay (ELISA) was employed to analyse the serum immunoglobulin concentrations. White blood cells profile was estimated by counting 200 cells . Results showed a significant increase (p < 0.03) of serum IgG, IgA and IgM in the drug addicts (6.93 ? 1.53g/l, 2.90 ? 1.13g/l and 1.72 ? 0.73g/l, respectively) compared to those in the cohort controls (6.52 ? 1.05g/l, 2.61 ? 0.83g/l and 1.52 ? 0.59g/l, respectively). A significant (p = 0.00) decrease of peripheral lymphocytes (51.8 ? 15.2 vs. 71.9 ? 11.5) was noted in the drug addicts. Monocytes (8.3 ? 4.9), neutrophils (128.2 ? 18.9) and eosinophils (11.4 ? 5.8) were found to be increased in the drug addicts against those in the controls (5.2 ? 2.5, 113.2 ? 13.0 and 9.6 ? 5.8, respectively). Multiple drug abuse for longer period had resulted in a significant (p < 0.05) decrease of serum immunoglobulins and lymphocytes. The longer period of addiction had also made a significant (p < 0.05) decrease of eosinophils (p = 0.05) and an increase of monocytes and neutrophils. Sex with multiple sexual partners had shown a significant (p < 0.01) decrease of serum immunoglobulins and eosinophils.