We report a case of fibrinoid reaction after diabetic vitrectomy surgery. Our case report describes a male patient with severe fibrinoid reaction with both intravitreal fibrin bands and subretinal fibrin and fluid following vitrectomy for diabetic retinopathy. He was managed initially with posterior subtenon and suprachoroidal injection of triamcinolone as well as intravitreal injection of tissue plasminogen activator (TPA). Fluid-air exchange and air-fluid exchange were also performed to remove the fibrin degradation product. 1 millimeter of air tamponade was placed in the vitreous cavity to displace the remaining subretinal fibrin. During this patient's follow-up, the patient's OCT including ultrawide-field OCT showed transvitreal fibrin bands, subretinal fibrin, as well as subretinal fluid in the right eye. The degradation of intravitreal fibrin bands as well as decrease in subretinal fluid were noted 2 days after intravitreal TPA and suprachoroidal injection of triamcinolone acetonide. The subretinal fibrin was partially reabsorbed and displaced after repeated injection of TPA and air tamponade placement 1 week later. Subsequent follow-up showed complete resolution of the subretinal fibrin and subretinal fluid as well as improved visual acuity. In summary, we describe a case of fibrinoid reaction after vitrectomy for diabetic retinopathy which was successfully treated. Wide-field OCT may also be used to assist in the recognition of this phenomenon.