AbstractEighty‐one cases of otosclerosis were operated upon, using the interposition of the posterior crus upon Gelfoam (R) from October 1960 to October 1961. The technique is described briefly and the results tabulated. Twenty‐four and eight‐tenths per cent of these had closure of the air‐bone gap, 54.4 per cent reached 10 db gap (total of 79.2 per cent); 7.2 per cent reached 15 db gap; 8.6 per cent reached 35 db gap; 3.7 per cent showed no gain; one case had a further conductive loss and one had a minimal cochlear loss. These last two had obliteration of the footplate by severe otosclerosis. One‐half of the 14.8 per cent revised were done with good improvement.The advantages of the operation are several: Good hearing can be obtained, no permanent foreign substance is used, the stapedial tendon is still functional in preventing acoustic trauma and displacement of crus into the vestibule; there is no evidence of cochlear damage due to surgery.