This study was intended to find out the factors affecting to the IADL, allowing objective assessment of physical function status of increasing elderly populations. The subjects of 635 elderly persons aged over 65 years old who live in Taejon metropolitan city were interviewed during the two-month period from June to July of 2000. The IADL of Older American Resources and Services(OARS), developed in Duke medical college of USA, was interpreted for use. The study results were statistically processed using SPSSWIN(ver 10.0) and conferred the following results: 1. Among the seven items of IADL, the women showed higher rates of 'yes' in items about using the telephone, getting to the places out of walking distance, going shopping for groceries, taking their own medicine while outnumbered by the men only in the item about managing their own money, without significant differences between them in items about preparing their own meals and doing their own housework. 2. In terms of IADL scores, $82.0\%$ of subjects showed the normal range of scores and $18.0\%$ were under the normal range, meaning dysfunction IADL. Specifications of general characteristics revealed that more dysfunctional were the male subjects, the higher age groups who are more than 75 years old, the higher educated groups, the groups who live in nursing homes, the groups without a spouse. 3. Based on daily activities, lower scores of IADL were found in the subjects who don't go out, who don't have recreational activities, who don't attend elderly gatherings in their neighborhood, who don't hold social meetings. Specifications of psychological traits revealed that more dysfunctional were IADL in the subjects who don't feel satisfied with their lives of the past or the present, who have a deep feeling of isolation, and who don't have the will to live. 4. Among 7 items of health habits, only the subjects who don't regular exercise had lower scores of IADL than those who do. According to HPI, the lower HPI, the more dysfunctional. 5. Based on the factors associated with IADL, the odds ratio of the subjects who don't live together with their families were 1.53 times that of the ones who do, who are educated 3.22 times that of the ones who are not, who don't have spouses 2.09 times that of the ones who do, who don't go out 4.35 times that of the ones who frequently go out, who don't recreational activities for an interest 2.64 times that of the ones who do, who don't attend elderly gatherings in their neighborhood 1.47 times that of the ones who do, who don't hold social meetings 2.23 times that of the ones who do, who don't feel satisfied with their present living 1.43 times that of the ones who do, who have a feeling of isolation 1.53times that of the ones who don'1, who have the weak will to live 3.21 times that of the ones who have the strong one, and who don't regular exercise 2.45 times that of the ones who do. 6. Logistic regression analysis of the study results found that such factors are significantly related as the degree of education, with/without spouse, social meetings, the will to live, and regular exercise, and that higher rates of dysfunctional subjects were in the more educated group, in the group without spouse, in the group who don't frequently go out, who don't have social meetings, who have the weak will to live, and who don't exercise.