The husbands of women undergoing mastectomy have been introduced as the patient’s primary caregivers. This research was conducted to investigate the lived experiences of Iranian Muslim husbands of women undergoing mastectomy. In this phenomenological research, 18 participants were interviewed, and Van Menan’s method of interpretation was used to interpret the data. 8 themes were extracted from the data analysis: physical problems, living in the shadow of fear and discomfort, and destiny is not blameless, modified roles, marital coldness, imposing a financial burden, spiritual care, and support failure. It is concluded that the husbands of these patients need comprehensive support, and the current support is not enough.