We report a case that developed acute postoperative endophthalmitis after transconjunctival sutureless vitrectomy using the 23-gauge system. A 66-year-old man underwent non-sutured 23-gauge pars plana vitrectomy for epimacular membrane. Since the patient developed signs of acute endophthalmitis and decreased visual acuity to counting fingers on the second postoperative day, re-vitrectomy with silicone oil was performed. The patient responded well to re-vitrectomy, injection of silicone oil and intravitreal antibiotic injections. Methicillin resistant Staphylococcus epidermidis was cultured from vitreous samples. Silicone oil was extracted at 11 months. The patient remains stable at 14 months with a final visual acuity of 20/50.