People with substance use disorders frequently present life stories marked by suffering and loss. Few studies have assessed the role of bereavement of a significant person in the drug dependent population. Aim: This study explored the loss of a significant person among 196 bereaved drug dependent patients before and after the age when they consider that their drug consumption increased. Methods: Socio-demographic characteristics, bereavement and drug related variables were examined. Perceived relationship between the significant loss and drug consumption was also assessed. Complicated grief symptomatology was measured by the Spanish version of the Inventory of Complicated Grief (ICG). Results: 83.2% of all participants stated that, after suffering the loss, they increased drug consumption. 12.3% of the patients who first increased drug consumption and after suffered the loss of a significant person reported a relapse after the loss. However, 54% of the participants who first experienced the loss and after increased their drug consumption did not perceive any relationship between the loss and their own drug consumption. The most frequent losses were the parents (father and mother), sibling being the third most significant loss. 34.2% of patients reported symptoms of complicated grief. Conclusions: Results show a relationship between the loss and the important increase of substance consumption. This study suggests the importance of including the process of grief psychotherapy within the treatment of drug dishabituation for those cases which presented symptoms of complicated grief