Background: Many children are affected by parental substance use disorder. Beardslee’s family intervention (BFI) is a family-based psycho-educative method for children of mentally ill parents, used in psychiatric practise in several Nordic countries. The method has also been used to some extent when a parent suffers from substance use disorder. Aims: The aim of the study was to explore the family members’ experiences of the BFI when a parent has a diagnosis of substance use disorder, to gain new knowledge about the process of the BFI in this area. Methods: Ten children and 14 parents were interviewed about their experiences 6 months after a BFI. The interviews were analyzed by qualitative content analysis. The children’s psychological symptoms were measured by the Strengths and Difficulties Questionnaire at baseline and after 6 months. Results: Increased openness about the substance use disorder in the families was a recurrent theme throughout the material and a central issue reported in the children’s experiences. The children had a high level of psychological symptoms according to the SDQ at baseline, but the majority of them felt that the BFI made a positive difference in their families and for themselves. The parents reported improved wellbeing of their children. Conclusions and clinical implications: Positive experienced effects for children and parents are reported in families with parental substance use disorder, with possible connection to use of BFI. The present study suggests that Beardslee’s family intervention is applicable as a preventive method for children in families with a parent suffering from substance use disorder.