Purpose To evaluate corneal endothelial changes after hyperopic laser in situ keratomileusis (LASIK) considering overestimation and underestimation of the cell count measurement. Setting Department of Ophthalmology, Nara Medical University, Nara, Japan. Methods The data were from the clinical trial of the Nidek EC-5000 excimer laser for hyperopic LASIK. The mean correction was 3.59 diopters (D) ± 1.54 (SD) (range 2.0 to 6.0 D). Using noncontact specular microscopy, the corneal endothelial changes in 25 eyes of 15 patients who had hyperopic LASIK were measured. Follow-up ranged from 6 months (n = 25) to 1 year (n = 21). The overestimation and underestimation of the corneal endothelial cell count that would occur after +5.0 D hyperopic LASIK was hypothetically calculated. Results The measured endothelial cell count per 1.0 mm 2 did not significantly decrease up to 1 year after hyperopic LASIK (preoperatively, 2508 ± 395; at 1 year, 2814 ± 349). The hypothetical calculation revealed that a +5.0 D hyperopic correction corresponded to a 0.1% underestimation of the corneal endothelial cell count. Conclusions Underestimation of the corneal endothelial cell count after hyperopic LASIK was negligible. Hyperopic LASIK with the Nidek EC-5000 excimer laser did not significantly decrease corneal endothelial cells up to 1 year after surgery.