To report a case of endophthalmitis following 25-gauge transconjunctival sutureless vitrectomy.Observational case report.An 87-year-old male who underwent sutureless 25-gauge vitrectomy developed unilateral endophthalmitis. Vitreous culture revealed Staphylococcus coagulase-negative bacteria. He was subsequently treated with intravitreal antibiotics and oral prednisone.The endophthalmitis resolved with a best corrected visual acuity of 6/200 with the presence of an epiretinal membrane.Possible contributing factors to endophthalmitis following sutureless vitrectomy include decreased vitreous irrigation/lavage, lack of a watertight wound, and/or vitreous wicking, all of which may promote intraocular bacterial entrance. A sutureless vitrectomy system may increase the risk of vitrectomy-associated endophthalmitis.