We examined the relationship between intrinsic religiousness and well-being, with control-related religious coping and self-efficacy for coping with cancer as potential mediators of this relationship among cancer patients. In a cross-sectional design, 179 ambulatory cancer patients completed measures of intrinsic religiousness, religious coping, self-efficacy for coping with cancer, well-being, and demographic variables. Type of cancer, stage of cancer, and time since diagnosis were collected from electronic medical charts. In a path model, the positive association between intrinsic religiousness and three types of well-being—physical, functional, and social—was fully mediated by active religious surrender and self-efficacy for coping with cancer. In addition, the negative association between passive religious deferral and all four types of well-being—physical, functional, social, and emotional—was fully mediated by self-efficacy for coping with cancer. Finally, there was a negative direct association between pleading for God’s direct intercession and emotional well-being. These findings suggest pathways by which intrinsic religiousness and control-related religious coping are linked to various dimensions of well-being among cancer patients.