Purpose: To determine the efficacy of immediate pars plana vitrectomy as the primary treatment for acute endophthalmitis in patients with a visual acuity (VA) of hand motion (HM) or better. Methods: A total of 149 patients who were referred to a single center for acute endophthalmitis after cataract surgery over the 13-year study period were retrospectively analyzed. Only patients presenting with a VA of at least HM were included. Patients were initially treated with either primary vitrectomy or intravitreal antibiotic injection alone, and their visual outcomes and reintervention rates after initial treatment were compared. Results: There was no significant difference in the proportion of good (final VA ≥20 / 40) and poor (VA ≤ counting finger) visual outcomes between the groups. However, subgroup analysis of patients with a VA of HM (92 eyes) showed that the incidence of reintervention (14 of 72 eyes [19.4%] vs. 9 of 20 eyes [45.0%]) and poor visual outcomes (10 of 72 eyes [13.9%] vs. 8 of 20 eyes [40.0%]) were lower after prompt vitrectomy than after intravitreal antibiotic injection alone (p = 0.019 and p = 0.022, respectively). For those with a VA of at least counting finger, no significant difference was observed between the groups. Conclusions For patients with endophthalmitis presenting with a VA of HM, performing a prompt vitrectomy reduced the incidence of reintervention and poor visual outcomes than the administration of intravitreal antibiotics alone. Our results suggest that primary vitrectomy for patients with endophthalmitis presenting with a VA of HM could be more beneficial than intravitreal antibiotic injection alone.