Purpose <p>To assess the effect of anterior chamber depth on corneal endothelium using specular microscopy following uneventful phacoemulsification among cataract patients with different axial lengths.</p> Methods <p>The study was conducted in a quasi-experimental design including 300 eyes of 300 patients with grade three age-related nuclear cataract distributed equally based on their axial length into three equal groups. All eyes had grade three nuclear cataract. All patients underwent phacoemulsification using the same settings. They were assessed preoperatively and postoperatively at one week, one month and three months using specular microscopy. Outcome measures included endothelial cell density, axial length (AL), anterior chamber depth (ACD), ultrasound time (UST), cumulative dissipated energy (CDE) and intraoperative balanced salt solution (BSS) volume.</p> Results <p>There were no significant differences (<i>p</i> &gt; 0.05) between study groups regarding age, cataract density, UST, CDE and BSS volume. The endothelial cell density decreased significant (<i>p</i> &lt; 0.001) postoperatively in all groups through the follow up period. However, the amount of change decreased as the end of follow up was approached. A significant negative correlation was found between amount of endothelial cell loss and ACD. However, no significant correlation existed between AL and ACD or ECL.</p> Conclusions <p>Endothelial cell density changes were significant following phacoemulsification. These changes were more in patients with shallow anterior chamber regardless of the axial length. Surgeons should adjust their surgical pattern considering our results.</p>