Background: Recreational drugs have a significant impact on the lives of drug users, their close families and friends, as well as their society. Social, psychological, biological, and genetic factors could make a person more prone to using recreational drugs. Finger and A-B ridges (dermatoglyphics) are formed during the first and second trimesters of fetal development, under the influence of environmental and genetic factors. The aim of our study was to investigate and evaluate a possible link between dermatoglyphics and opium usage.Methods: The pattern of dermatoglyphics - finger and A-B prints - obtained from a group of opium users (121 patients) was compared to those obtained from a group of opium non-users (121 patients) from Birjand, Iran. The results were analyzed using chi-square, t and Mann–Whitney tests.Findings: The results showed that although A-B ridges of palms and fingers in our study group were higher compared to the control group, there was no significant difference between these groups. The only significant difference was the fingerprint patterns of the left ring finger in the study group, which lacked the arch pattern and had less loop patterns. The dominant type of fingerprint in the left ring finger was the whorl. In our opium user group, the arch and loop fingerprint patterns were heterogeneous and significantly different in comparison with the control group (P < 0.01).Conclusion: These findings suggest that a genetic factor may increase the predisposition to recreational drug usage. Further research is required to confirm this possible impact of genetic factors on the addiction process.