Until recently, aminoglycoside antibiotics were the cornerstone for the treatment of severe infections. The rationale for using combination therapy containing beta-lactams and aminoglycosides was not only to broaden the antimicrobial spectrum but also to achieve enhanced bacterial killing by synergism and to prevent the emergence of antibiotic resistance. However, with the advent of new potent broad-spectrum and highly bactericidal antibiotics, the necessity of combining beta-lactams with aminoglycosides should be reassessed. This review questions the use of aminoglycosides in three severe infections frequently observed in intensive care units, nosocomial pneumonia, nosocomial sepsis and severe diffuse peritonitis. A review of the literature suggests that the addition of an aminoglycoside to a broad-spectrum beta-lactam does not improve the outcome in nosocomial pneumonia and severe diffuse peritonitis. However, the lack of large prospective studies in severe sepsis or septic shock makes it impossible to draw any conclusion about the addition of an aminoglycoside, and the administration of these agents must be decided on an individual basis.