Background and aim: Evidence suggests that opioid abuse may exert adverse immunomodulatory effects on innate and adaptive immune responses. This research aimed to understand the impact of opioids and their detoxification on the percentage of dendritic cells (DCs) in opium addicts. Material and methods: In this study, 38 chronic opium addicts were divided into two groups. One group received methadone, while the other was treated with buprenorphine. Flow cytometry was employed to analyze dendritic cell subsets including, CD11c+ myeloid dendritic cells and CD123+ plasmacytoid dendritic cells, and surface marker expression including, HLA-DR, CD11c, CD123. Results: A significant difference was observed in the percentages of peripheral blood myeloid DCs between the addicted subjects and the control group. However, no significant change was noted in the percentage of plasmacytoid DCs between the two groups. Detoxification with methadone exacerbated the reduction of myeloid DCs in the peripheral blood of addicts, whereas the buprenorphine detoxification regimen appeared to correct this decrease. Conclusion: Dendritic cells play a crucial role in both innate and adaptive immune responses. Thus, the impairment caused by opium in these cells could increase the occurrence of infectious diseases. The findings suggest that buprenorphine may be advantageous in ameliorating the immunological disorders associated with opium abuse.