Dermatologic infections are among the most commonly experienced complications of cancer and anti-cancer therapy. Alterations in host immune function secondary to the underlying malignant process and/or its treatment have been linked to an increase in the risk of infections. The skin and its appendages (i.e., hair and nails) represent the first line of defense against infectious microorganism; its dysfunction as a physical barrier and an immunologic organ in cancer patients leads to an increased susceptibility to infectious organisms. Moreover, a cancer patient's vulnerable state facilitates dissemination of infections to other sites, secondarily involving the skin. This chapter delineates dermatologic infections that are unique to cancer patients as a result of their underlying malignancies and associated comorbidities as well as those resulting from antineoplastic therapies.