Father engagement in addictions services with substance‐using mothers may be neglected, resulting in mothers’ poorer engagement and retention in addictions services, and subsequent compromised family health. To determine the extent and nature of father exclusion in ante‐partum, partum and post‐partum addictions services, and whether father exclusion affects mothers’ engagement and retention in services, a mixed methods study, using qualitative and quantitative methods, will be conducted at Fir Square Combined Care Unit, BC Women’s Hospital.