Aminoglycoside antibiotics were among the first antibiotics discovered and used clinically. Although they have never completely fallen out of favor, their importance has waned due to the emergence of other broad-spectrum antibiotics with fewer side effects. Today, with the dramatically increasing rate of infections caused by multidrug-resistant bacteria, focus has returned to aminoglycoside antibiotics as one of the few remaining treatment options, particularly for Gram-negative pathogens. Although the mechanisms of resistance are reasonably well understood, our knowledge about the mode of action of aminoglycosides is still far from comprehensive. In the face of emerging bacterial infections that are virtually untreatable, it is time to have a fresh look at this old class to reinvigorate the struggle against multidrug-resistant pathogens.