Netilmicin sulfate, the 1-N-ethyl derivative of sisomicin, is a new aminoglycoside recently released for use in Canada and not yet released in the U.S. Its place in therapeutics, compared with gentamicin (G), tobramycin (T), and amikacin (A), is not yet established. Preliminary work in animals has suggested a lower incidence of nephrotoxicity and ototoxicity than with other aminoglycosides, and in vitro work has suggested some activity against G/T-resistant organisms. However, netilmicin appears to be virtually identical to G,T, and A in antimicrobial spectrum (except for its poorer activity against P. aeruginosa), human toxicity, and clinical use. For G/T-resistant organisms, amikacin is still the aminoglycoside of choice. In summary, netilmicin has not been demonstrated to have significant advantages over other aminoglycosides (G,T,A), and it is more expensive; thus, its potential value is limited.