Background: Relatives' participation in the care of patients with cancer in hospital is essential to both patients and relatives. Although the meaning of relatives' participation has been recognized, knowledge about how patients experience this participation is rare. Aims: To describe the experiences of patients with cancer of the realization of relatives' participation in the hospital care. Materials & Methods: A qualitative study with semi‐structured interviews of patients with cancer (n=21) were conducted. Data was analyzed using inductive thematic analysis. Results: Three main themes were identified among patients' experiences: Relative as part of the patient's care, Relative supporting patient's coping process, and Hospital enabling or preventing relatives' participation. The relatives were available for patients in seeking information and in the decision‐making process. They helped with the daily needs of the patient, and supported patients emotionally and by managing everyday life at home. The behavior and attitudes of the healthcare professionals and the special nature of the hospital played a central role in the experiences. Conclusion: The role of relatives is an important part of the coping process and care of patients with cancer in the hospital.