(i) The objective was to determine the range of bone levels of cefuroxime and flucloxacillin achieved after one intravenous (IV) administration of different dosages of cefuroxime and flucloxacillin. (ii) Six groups of five patients participated in the study. The first three groups (A-C) received respectively 1500 mg, 1000 mg, and 500 mg cefuroxime intravenously and the second three groups (D-F) received 2000 mg, 1500 mg, and 1000 mg flucloxacillin intravenously. (iii) Parenteral administration of cefuroxime and flucloxacillin resulted in measurable bone concentrations in all patients. (iv) Large inter-individual variation in bone concentration was observed. (v) The bone concentrations of IV cefuroxime were higher (1500 mg, p = 0.0057; 1000 mg, p = 0.0260) than those of flucloxacillin. The bone concentrations of cefuroxime and flucloxacillin were dose dependent.