In 1978, I reported on the diagnostic criteria and therapy based on the treatment of 34 cases of perilymph fistula. Of that group, 20 patients had no hearing loss associated with the fistula. Since that time, an additional 30 cases of fistula--15 without hearing loss--have been seen and treated operatively. The 30 significant variables of history and physical findings identified in the first study were statistically reviewed, along with a new finding that seems highly significant. Twenty-three of the 26 new cases so evaluated had a positive "eyes-closed turning test" (staggering when turning to the side of the lesion after walking with eyes closed). A further finding has been the presence of an abnormally placed round window membrane, in most cases involving the round window. The total operative population of fistulas, both those with and without hearing loss, is reviewed to identify the operative technique best suited for each window and the graft material most likely to succeed. Perichondrium is the choice tissue for graft material, except for very small fistulas at the annular ligament. The graft must be held firmly in place, with either a prosthesis or appropriate packing, carefully avoiding adhesions between the round window and the tympanic membrane.