The open technique in middle ear surgery has besides a higher security concerning the recurrence of disease, some disadvantages ; life-long care for the cavity, often discharging granulation, and vestibular vertigo due to the lack of labyrinthine protection. Most of the disadvantages can be avoided by the reconstruction of posterior canal wall and obliteration of the mastoid cavity, for which many different technique have been described in literature. The authors recommand a method ; the reconstruction of the posterior canal wall and the obliteration of the mastoid cavity with cortical bone chips. The technique can be used for one-stage surgery. The result were as follows ; 1) Easily available near the operation field without complication. 2) Maintenance of nearly normal external auditory canal. 3) Shorter duration of postoperative care. 4) More advantages for reconstruction of ossicular chain or use of artificial hearing apparatus.