Descemet's membrane detachment (DMD) is one of the rare complications seen during or after cataract surgery. It can cause permanent corneal decompensation if untreated or not reattached spontaneously. A patient with an extensive DMD (involving approximately upper two-thirds of the cornea) during uncomplicated phacoemulsification surgery is reported. After the aspiration of cortical remnants, Descemet's membrane was detached progressively from the clear corneal incision. Descemet's membrane was reattached at the end of the procedure using an air bubble injection. However, DMD was observed again the day after surgery. It was successfully treated with intracameral injection of 0.2 mL volume of 14% perfluoropropane (C(3)F(8)) gas with resultant immediate resolution of his corneal edema. It is believed that early surgical intervention (if possible intraoperatively) with intracameral injection of 14% isoexpansile mixture of C(3)F(8) is a safe and efficient treatment modality for DMD. Appropriate and prompt management may prevent the complications and visual loss.