AIM: To assess the effects of small incision lenticule extraction (SMILE) surgery on the corneal endothelium at 1d to 1mo postoperatively. METHODS: A retrospective, observational study was conducted on 47 patients (47 eyes) who received SMILE surgery. Patients were grouped according to contact lens wear condition. The corneal endothelium was examined preoperatively and at 1d, 1wk and 1mo postoperatively. The corneal endothelium was analyzed for endothelial cell density (ECD), percentage of hexagonal cells, and coefficient of variation (CV) of cell size. RESULTS: There were no significant decrease in the ECD, percentage of hexagonal cells or increase in CV at 1d, 1wk and 1mo postoperatively (P>0.05). However, there was a small increase of ECD by 2.88% in contact lens wearers (78.26±113.62 cell/mm2, P<0.05). CONCLUSION: SMILE has no significant adverse effects on the corneal ECD and morphology during 1mo follow-up time.