urpose: The aim of the study was to investigate the possible adverse effect of intracameral cefuroxime (ICC) on corneal endothelium by comparing it with subconjunctival gentamycin (SCG) injection. Methods: Patients were divided in two groups; ICC (1 mg/0.1 ml) and SCG (40 mg/ml). Corrected distance visual acuity, anterior segment examination, intraocular pressure measurement, specular microscopy (endothelial cell density, coefficient of variation (CV), hexagonality, and central corneal thickness (CCT) were performed before surgery and at postoperative controls on week 1, month 1, and month 3. Results: Fifty-one eyes received ICC, 37 eyes SCG, and the mean ages of the patients were 70.0±5.5 and 69.2±6.6 (p=0.644). Endothelial cell loss at month 1 was 17.07% in ICC and 16.75% in SCG group (p=0.899). CCT returned to pre-operative values in SCG group at month 1 (p=0.483). Whereas in ICC eyes, a statistically significantly higher CCT still persisted at month 1 (p=0.015). CV showed no statistically significant difference at three post-operative visits compared to baseline in SCG group. Whereas in ICC group, a statistically significant increase was observed in CV at week 1 (p=0.000) and month 1 (p=0.012). At month 3 visit, a statistically significantly lower hexagonality was observed in ICC when compared with SCG (p=0.019). Conclusion: Results of our study showed that the licensed ICC use after phacoemulsification is safe as SCG in clinical point of view. However, abnormalities in CCT, CV, and hexagonality suggest subclinical endothelial toxicity of cefuroxime.