Does the impact of stigma on the self differ by illness type? This study focuses on a comparison of the effects of the stigma associated with HIV/AIDS and cancer on self-esteem, body image, and personal control. We test the hypothesis that individuals' perceptions of stigma account for significant differences in the impact of an illness on the self. We examine four dimensions of perceived stigma: social rejection, internalized shame, social isolation, and financial insecurity. In turn, we consider how these dimensions medicate the effects of HIV/AIDS and cancer. Our sample includes 130 persons with HIV/AIDS and 76 persons with cancer. We control for illness severity by including a measure of functional health status that is based on participants' subjective perspectives of the severity of their symptomatology. Our findings provide additional support for modified labeling theory; however, our findings also point to the dimensionality of stigma and its differential negative impact on particular elements of the self, regardless of illness type.