Objectives: Treatment of repetitive negative thinking (RNT) focuses rather on individual than group cognitive behaviour therapy (CBT) treatment. Additionally, little is known on how clients experienced these interventions. This study investigates clients' experiences on participating in a CBT group intervention targeting RNT (RNT-G). Design: Of the 80 participants, 11 were randomly selected for an in-depth, semi-structured interview after treatment. Interviews focused on what participants experienced as important on group aspects, offered interventions, homework tasks, and possible changes. Methods: All participants were adults, diagnosed with major depressive disorder and/or generalized anxiety disorder and being currently in mental health care treatment.