AIM: To evaluate the safety of using 0.03% trypan blue under air for anterior capsule staining in cataract surgery. METHODS: The current study involved a retrospective analysis of the medical records of 86 patients with vitreous hemorrhage, who underwent pars plana vitrectomy and cataract surgery. The patients were classified into two groups. The trypan blue group (n=45) comprised patients who underwent anterior capsule staining with 0.03% trypan blue under an air bubble. The control group (n=41) comprised of patients who underwent intracameral illuminator-assisted capsulorhexis. The status of endothelial cell density (ECD) in both the groups was analyzed. RESULTS: The trypan blue group displayed significant decline in ECD at 1mo (7.91% loss, P<0.001) and 3mo (9.65% loss, P<0.001) after the surgery, whereas no significant changes were observed in the control group. Moreover, the number of patients who did not display a postoperative decline in ECD was significantly higher in the control group (43.9%; 18 patients) than in the trypan blue group (17.1%; 7 patients, P=0.004). CONCLUSION: Anterior capsule staining with trypan blue under the air bubble would not be as safe as the intracameral illuminator. The ECD loss might be attributed to the air bubble rather than to the deleterious effects of 0.03% trypan blue. Further studies are required to clarify this.