The influence of drug abuse on social support has been explored in different studies; however, the social support networks of individuals with substance-related disorders have not been described in comparison with individuals without these diagnoses. Therefore, this study aimed to assess the differences in the perception of men with and without substance-related disorders, specifically with regards to their social support network and the structural characteristics of their personal networks. Data were collected using psychometric scales and analysed through statistical methods that compared the two study groups. One-hundred patients participated in this study; participants were recruited at two public health service centres in an inner city of Brazil. The results showed that individuals with substance-related disorders displayed less satisfaction with their social support network and a lower density in their personal networks compared with the group without substance-related disorders. From these results, it appears that professionals involved in caring for these patients should implement interventions that improve the support networks of this patient population to facilitate both prevention and recovery.