The cutaneous T-cell lymphomas are a group of T-cell neoplasms which present with the skin as the initial site of involvement. Mycosis fungoides is the most common type of cutaneous T-cell lymphoma. Mycosis fungoides presents initially as cutaneous patches, which may resemble other common dermatologic disorders. In many patients the disease never progresses beyond the patch stage, but in some there is progression to cutaneous plaques, and there may be further progression to cutaneous tumors and/or erythroderma. The extent and type of skin involvement and the presence or absence of lymph node or visceral involvement are importantclinical predictors of survival. The survival rate of patients with the earliest disease stage is not significantly different than that of age-matched controls. The vast majority of patients with mycosis fungoides do not die of the disease.