After dacryocystorhinostomy (DCR), a silicon tube is generally inserted into the superior and inferior puncta and then passed through the canaliculi to the opened lacrimal sac. Instead, we insert a T-sheet into the opened sac after DCR. In this method, an incision is made on the ridge of the nose, and a flap is elevated. A DCR diamond burr is used to remove the bone and expose the lacrimal sac and the nasolacrimal duct surface. Then, a vertical incision is made in this region. Next, a T-sheet is made from a Penrose drain tube. The horizontal part of the T-sheet is inserted into the sac and is left in the sac for 2 to 4 weeks. Twenty sacs in 17 cases have been subjected to the above method in the past 14 years. Two cases required further surgical procedures, and the success rate was 90%. Physicians who are familiar with endoscopic sinus surgery can easily perform the reported procedure.