The purpose of this study was to investigate the penetration into the aqueous humor of cefuroxime after a single oral dose as cefuroxime axetil. Fourteen patients scheduled for cataract extraction received a single oral dose of cefuroxime axetil corresponding to 500 mg of cefuroxime 2–8 h preoperatively. Aqueous humor samples were obtained at the beginning of the cataract surgery and blood samples were drawn at the time of anesthesia. Cefuroxime levels were determined by high-performance liquid chromatography. The aqueous levels were (mean ± SEM) 0.48 ± 0.13 μg/ml from 3 to 8 h after administration. Serum levels averaged 3.80 ± 0.58 μg/ml. These data indicate that detectable levels of cefuroxime, exceeding the MIC of some bacterial species that frequently cause intraocular infections, may be achieved in uninflamed eyes after a low dose of cefuroxime axetil.