The present work focuses on the so-called dual diagnosis (DD): bipolar disorder (BD) associated with substance use disorders (SUD). Although the psychiatrists who treat patients with BD and physicians in charge of patients with SUD frequently find this association with DD, unfortunately there are few scientific works that have studied this association. The Spanish Working Group on Bipolar Disorders in Dual Diagnosis reviewed the published material using a Medline search and selected the most relevant articles. Following this, the Work Group developed an expert consensus in DD and finally, a survey was performed among a group of experts in this disorder to cover the areas that were not fully addressed by the scientific evidence or in those areas in which the Work Group was unable to reach a consensus. We conclude that, in view of the above, establishment of a consensus is a valid tool to complement the current scientific evidence.