Background: Depression in conjunction with cardiovascular disease (CVD) is associated with worsening in CVD, higher mortality, and poorer quality of life. Despite the poor outcomes there is a treatment gap of depression in CVD patients. Recently we found that an Internet-based cognitive behavioral therapy (iCBT) tailored for CVD patients led to reduced symptoms of depression. However, we still have little knowledge about CVD patients’ experiences of working with iCBT. The aim of this study was therefore to explore CVD patients’ experiences of engaging in a tailored iCBT program. Methods: A qualitative interview study using inductive thematic analysis. Data was obtained from 20 patients with CVD and depressive symptoms who had participated in a randomized controlled trial (RCT) evaluating the impact of a nine-week iCBT program on depression. Results: Three main themes emerged: (1) Taking control of the disease, (2) Not just a walk in the park, and (3) Feeling a personal engagement with the iCBT program. The first theme included comments that the tailored program gave the patients a feeling of being active in the treatment process and helped them achieve changes in thoughts and behaviors necessary to take control of their CVD. The second theme showed that patients also experienced the program as demanding and emotionally challenging. However, it was viewed as helpful to challenge negative thinking about living with CVD and to change depressive thoughts. In the third theme patients reported that the structure inherent in the program, in the form of organizing their own health and the scheduled feedback from the therapist created a feeling of being seen as an individual. The feeling of being acknowledged as a person also made it easier to continuously work with the changes necessary to improve their health. Conclusions: Engaging in an iCBT program tailored for patients with CVD and depression was by the patients perceived as helpful in the treatment of depression. They experienced positive changes in emotions, thoughts, and behaviors which a result of learning to take control of their CVD, being confirmed and getting support. The patients considered working with the iCBT program as demanding and emotionally challenging, but necessary to achieve changes in emotions, thoughts, and behaviors.