Background: The experience of caring for a family member with cancer is associated with several care‐related problems and challenges for the caregiver. The comprehensive and in‐depth understanding of the trials and tribulations of caregiving can be a step towards resolving the problems faced by family caregivers of these patients. Aim: The present study aimed to explore challenges faced by Iranian family caregivers of cancer patients. Materials and methods: The present qualitative study was conducted through in‐depth semi‐structured interviews held with 21 family caregivers of cancer patients selected through purposive sampling. Interviews continued until saturation of data. All interviews were recorded, transcribed and analysed through conventional content analysis. Finding: The codes extracted from interviews produced four main themes, including ‘confusion’, ‘uncertainty’, ‘disintegration’ and ‘setback’, which collectively caused suffering for family caregivers. Conclusion: Care provided in an atmosphere of suffering and discontent diminishes caregiver's quality of life and quality of patient care. Health planners should therefore consider the challenges and sufferings faced by family caregivers and should seek to obviate them through appropriate plans.