Abstract Neoplastic disease and its treatment lead to specific immune defects that predispose to specific infections. As the management of cancer has changed, so has the spectrum of infection with which it is associated. neutropenia, T-cell defects, B-cell defects, and splenectomy lead to either specific illnesses or more severe manifestations of infection. Interruption in the normal barriers of the skin and mucous membranes due to the tumor itself or its treatment also predisposes to infection. Investigation is under way to determine the role of newer modalities (e.g., hematopoietic growth factors, interleukins, and interferons) in decreasing the number and severity of such infections.