Hypotony from an inadvertent filtration bleb developed in the eye of a 66-year-old woman 1 year after phacoemulsification cataract surgery. The hypotony was treated with an autologous blood injection over the previous phacoemulsification incision. This technique successfully treated the hypotony without additional ocular surgery. The authors report an effective alternative treatment for hypotony induced by an inadvertent filtration bleb.