Background: Heart failure (HF) continues to be a global health problem with its ramifications more pronounced in underdeveloped countries. Family members play a pivotal part in patient management which may influence the patient’s overall quality of life. Prolonged delay in attendance to health care facilities among patients indicates ineffective support from family caregivers. In the Tanzanian context, there is limited information about the experiences of family caregivers in caring for patients with HF. This study explored family caregivers' experiences in caring for HF patients.  Methods: A qualitative descriptive study design was conducted at Jakaya Kikwete Cardiac Institute in Dar es Salaam, Tanzania. A purposive sampling technique was used to select the potential participants. A sample size of 10 family caregivers of patients with HF was included in the study. Thematic analysis was used to derive the main theme and sub-themes. Results: Three major themes were identified: demands for supportive care, new caring role and lifestyle, and professional support in caring for patients with HF. Caregivers needed social and financial support to facilitate the caring process. Learning to provide the required care at the right time was the new role acquired by caregivers while failing to participate in social events and caregiving in an unfavourable environment were reported as challenges in caregiving. However, compliance with instruction and effective interaction among the nurses and caregivers were considered to be positive professional support. Conclusion: Caregivers need social and financial support to provide effective care to their patients. Caregiving is a learning process that needs continuous educational support to adapt to the new caring roles and challenges.  Nurses should conduct regular assessments to explore caregivers’ needs, challenges, and concerns and provide timely counselling that can facilitate coping.