The antibiotic spectrum, pharmacology, adverse effects, and therapeutic use of amikacin sulfate are reviewed. Amikacin, a semisynthetic analog of kanamycin, is highly active against most gram-negative bacteria including many gentamicin-resistant strains. Amikacin's pharmacologic properties have been studied extensively in both children and adults. It achieves high, predictable, and prolonged blood concentrations with a favorable therapeutic index. Amikacin does cause nephrotoxicity and ototoxicity; however there is no conclusive evidence that these toxicities differ from those caused by other major aminoglycosides. The effectiveness of amikacin sulfate in the treatment of serious gram-negative bacillary infections is well documented. Amikacin sulfate is an important addition to the antibiotic armamentarium of a hospital with high gentamicin or tobramycin resistance. In hospitals without substantial aminoglycoside resistance, its use is debatable because amikacin has not been shown to have increased clinical efficacy compared with the other aminoglycosides for infections caused by susceptible bacteria.