Aminoglycosides remain the cornerstone of antibiotic therapy for nosocomial, gram-negative bacillary infections despite the recent introduction of broad-spectrum beta-lactam antibiotics and quinolones with antipseudomonal activity. Initially, aminoglycosides were used as antiaerobic gram-negative antimicrobial therapy. Currently, they have a key role in many types of infections, such as gram-negative urosepsis and in febrile granulocytopenic patients, because of their established antipseudomonal activity. Empiric treatment of febrile episodes in granulocytopenic cancer patients with an aminoglycoside, in combination with an anti-pseudomonal beta-lactam, accounts for much of the aminoglycoside use. Amikacin is emerging as one of the most effective aminoglycosides on the basis of resistance rates, pharmacokinetic factors likely to affect clinical efficacy, safety, and overall cost of therapy.