Community-acquired Pneumocystis carinii pneumonia developed in a young adult patient with dyskeratosis congenita. His hospitalization ended fatally with disseminated candidiasis. Evaluation during the admission showed evidence of cellular immune dysfunction as indicated by skin test anergy and absent lymphocyte proliferation in an in vitro mixed lymphocyte culture. Treatment with transfer factor failed to reverse the cutaneous anergy or affect the clinical course. Dyskeratosis congenita is a rare multisystem disorder with prominent dermatologic manifestations; bone marrow failure or malignant neoplasm are common fatal outcomes. Immune system abnormalities are not classically considered a part of the disease complex. Serial evaluation of our patient's condition over several years suggests that depressed immune function, especially of the cellular limb, may evolve as a feature of clinical importance in these patients.