Total hip arthroplasty(THA) is applied to various hip diseases, and the results are different according to the disease entities. We have made the functional evaluation of three groups of the patients who had undergone THA in Seoul National University Hospital from 1981 to 1990: the first group-fused hips (28 hips of 27 patients), the second group partially ankylotic hips whose total range of motion were less than 60°(46 hips of 46 patients), and the third group-hips of ankylosing spondylitis (22 hips of 14 patients). The results were summerized as follows: No statistically significant difference was seen in the postoperative average Harris hip score between three groups. In the postoperative average range of motion, statistically significant difference was seen only between the first and second groups. Therefore, similar clinical results can be obtained from the THA in the fused hips to those of the partially ankylotic hips such as tuberculous or septic hip sequelae.