- Despite advancements in the treatment and supportive care of patients with malignant disorders, neutropenia remains the major side effect of most antineoplastic regimens. Infections occur frequently in neutropenic patients and are associated with considerable morbidity and mortality. The spectrum of infection continues to change, and is influenced by various factors including local epidemiology, the use of chemoprophylaxis, and the use of central venous catheters and other medical devices. Bacterial infections are common in the early stages of neutropenia, with fungal infections emerging if neutropenia persists beyond 7-10 days. Gram-positive organisms cause most bacteremic infections (although this trend appears to be changing), whereas infections at other sites are often caused by Gram-negative bacilli or are polymicrobial, especially if deep tissue infection is present. Candida spp., and Aspergillus spp., remain the most common fungal pathogens, although several opportunistic fungi have emerged. Resistance to antimicrobial and antifungal agents commonly used for the prevention and treatment of infections in neutropenic patients has become a significant problem. The prompt administration of appropriate, empiric, antimicrobial therapy, prior to the availability of microbiological culture results, is the standard of care. Up to date knowledge of the spectrum of infection and local susceptibility/resistance patterns, is critical. In this report, we describe the current spectrum of infection in patients with malignancies and neutropenia, and emphasize the fact that local and geographic differences are not infrequent. We recommend that individual institutions conduct periodic epidemiological surveys in order to have the latest data available for the optimal management of their patients.