a b s t r a c tIntroduction: Women with postnatal depression (PND) face significant barriers to treatment that may be overcome by internet based delivery of treatment. Demand for a self-help internet postnatal treatment offered via a parenting site was high, but attrition rates were also high. Aims: To gain patient perspectives on engagement and barriers to the Netmums' "Helping with Depression" treatment. Method: Semi-structured interviews were conducted with 17 participants selected from the Netmums trial. Results: Thematic analysis revealed motivators and barriers to treatment. Women reported that the flexibility and anonymity of internet interventions fit with their postnatal circumstances. They identified that the relevance of the intervention to their personal circumstances, expectations of motherhood, stigma about depression and motherhood, hopelessness about their ability to improve, previous negative experiences with treatment and treatment seeking, and a lack of practical and emotional support contributed to feelings of being overwhelmed. Women who felt more overwhelmed were more likely to discontinue treatment. Women suggested that support would reduce the impact of barriers and improve adherence. Discussion: Open access, self-help internet interventions are acceptable to women with postnatal depression, but it is critical to provide tailoring and support to help overcome barriers and improve treatment adherence.Crown