We report two infants treated with daptomycin for methicillin-resistant Staphylococcus aureus infection and describe peak and trough blood concentrations measured during therapy. The peak concentrations were 41.7 and 36.7 mcg ml(-1), and the 12-hour trough concentrations were 12.7 and 16.3 mcg ml(-1), respectively. Even though the infants received higher doses than adults, their drug concentrations were comparable to those observed in adults treated with regular dosing of daptomycin.