During surgical treatment of a patient with otosclerosis, the probability of success depends in large part on the extent of the surgeon’s experience. Therefore, predicting the preoperative severity of disease may help determine the choice of surgeon based on how experienced the surgeon should be. We conducted a study to evaluate the relationship between hearing thresholds and footplate thickness in otosclerosis patients who underwent stapes surgery. We used a qualitative method for measuring footplate thickness that was based on the simplicity or difficulty of opening the footplate. Our study population was divided into two groups; group 1 was made up of 66 patients whose footplates were easily opened with low pressure or with repeated motions by hand, and group 2 was made up of 14 patients whose footplate was either opened by drilling or not opened because it had been obliterated. We found that the patients in group 2, who had more severe disease, had significantly higher air- and bone-conduction thresholds than did the patients in group 1. According to our findings, otosclerotic patients with high air- and bone-conduction thresholds generally have more severe disease and thus require a more experienced surgeon.