Background: phacoemulsificationisthe preferred surgical procedure in treatment of cataract nowadays. Its outcome can be affected by health of the cornea, intra ocular pressure, manipulation and time of surgery in mature and white cataracts, trypan blue staining of the anterior capsule improves capsule visibility. Aim: To assess Trypan blue stain's effectiveness and safety after cataract surgery. Patients and methods: This prospective cohort study's was performed at Ophthalmology Department, faculty of Medicine, Zagazig University hospitals. Patients with cataract (nuclear II III) or PSC, age group from (20-60) and patients with more than 100 corneal endothelial cells per 2000 cells/mm² were covered by the research. They were divided into the case group and control group. All patients were subjected to history taking, complete slit-lamp examination including grading the density of the cataract and an indirect ophthalmoscopy examination. Results: There was significant decrease in ECD in both groups after one month of phaco surgery with statistically highly significant decrease in group 2 compared to group 1. The same was observed in hexagonality and coefficient of variance. Central corneal thickness showed no difference in change between both groups. Conclusion: There aren't significant alterations in the corneal endothelium one month postoperativelyafter staining anterior capsule by trypan blue 1% in phacoemulsification surgery.