Objectives Impairments in social cognition have been described as playing a major role in the maintenance of addictive behavior in substance abusers. This study aimed to investigate the Theory of Mind (ToM) ability of opiate-dependent (OD) patients and to explore whether TOM ability was correlated with length of substance abuse, age at onset of substance abuse and length of abstinence. Methods OD patients (N = 29) and non-dependent individuals (NDI) (N = 29) were submitted to the Theory of Mind Assessment Scale (Th.o.m.a.s.), a semi-structured interview, and to the Versailles-Lecture Intentionnelle en Situation (V-LIS), a movie paradigm in which participants have to infer the characters' intentions. Results The results confirmed a deficit in ToM ability in OD patients, with OD patients demonstrating poorer performance than NDI on both the V-LIS and the Th.o.m.a.s. The combination of perspective taking and reflecting on others' mental states was particularly difficult for OD patients. Furthermore, impairments in ToM abilities were not correlated with the age at onset of substance abuse or to the duration of substance abuse or abstinence. Conclusions The results suggest OD patients may have impaired social cognition, demonstrating deficits in even basic social interaction skills, which may constitute a risk factor for addiction. These findings underline the importance of developing interventions to improve social cognition ability during the rehabilitation of OD patients.