Background: The psychological difficulties and emotional impacts resulting from the substance use of close relatives constitute a large, underestimated and frequently unidentified health burden. The development of primary care mental health services in response to the Improving Access to Psychological Therapies initiative provides an opportunity to investigate this in more depth. Aims: A preliminary exploration of prevalence of IAPT service-users being treated for moderate-severe depression and/or anxiety who report that they have relatives with alcohol and/or drug problems. To explore the characteristics of the sample including comparison with those without a substance misusing relative. Method: One hundred service users completed a brief questionnaire. Routine data on depression and anxiety symptoms were accessed for the full consenting sample. Descriptive statistics were used to explore the family members of substance users and differences to the rest of the sample. Results: Twenty-two of the 100 IAPT service users reported having a close relative whose use of substances was of concern to them. The group with a relative who used substances were more depressed at the beginning of treatment than the rest of the sample. Conclusions: A significant number of people seeking psychological help for depression and anxiety within IAPT services reported being concerned about a close relative who misuses substances. They may be more distressed than those without a relative who misuses substances. Further exploration is warranted but preliminary findings indicate that this is an important research area with significant clinical implications.