Purpose: To evaluate the corneal endothelial cell density and Polymegathism after laser assisted keratomileusis with mitomycin C.Patients and Methods: One hundred and three eyes from 52 patients undergoing laser assisted sub-epithelial keratomileusis using mitomycin-C 0.02% for 30 seconds entered this study. Specular microscopy was utilized to study the corneal endothelial cells before and one year after the surgery to evaluate the endothelial cell density and polymegathism. The corneal thickness was measured before and one year after the surgery.Results: The mean endothelial cell density before surgery was 2870±368/mm2, which changed to 2828±300/mm2 one year after the surgery (P=0.182). Endothelial cell size variation coefficient was 24±7 before the surgery, which changed to 25±7 one year after the surgery (P=0.039). The average stromal ablation dept was 65 micron (22 to 131 micron) and the remaining corneal thickness one year after the surgery was 488±42 micron (405 to 567 micron) (p<0.001).Conclusion: Using mitomycin C (0, 02% for 30 seconds) during the laser assisted sub-epithelial keratomileusis did not significantly change the corneal endothelial cell density one year after the surgery but the change in polymegathism was significant