AIM: To assess whether the new microincision cataract surgery (MICS) induces less endothelium damages than the standard coaxial phacoemulsification.METHODS: Two hundred consecutive patients affected by age-related cataract were randomly assigned to undergo phacoemulsification using either standard coaxial phaco (SCP) or MICS. Central cornea and 12 o'clock endothelial cell count,cell size variation coefficient, percentage of hexagonality and central cornea thickness were measured before and up to one year after surgery.RESULTS: One hundred and seventy-three patients completed the trial. At the one-year follow-up visit, the loss of endothelium cells was 6.5204% in the MICS group and 8.726% in the SCP group (P＜0.00005). There was no significant differences between the two groups in terms of coefficient of variation in cell size, percentage of hexagonal cells,corneal thickness the day after surgery and variation of endothelial cell density measured both at the incision site and at the central cornea. In patients with hard cataracts, the increase in endothelial cell density loss was higher independently of the procedure.CONCLUSION: MICS induced a significant lower endothelial cell density loss than SCP.