The purpose of this study was to identify influencing factors adherence and dropout of aquatic exercise in patients who had been diagnosed chronic arthritis. Subjects were 54 patients with rheumatoid arthritis and osteoarthritis who had participated in the 6-week aquatic exercise program in Taejon metropolitan city. Data was collected from march 25 to April 25, 1999 through face to face and telephone interview. Result are as follows. Fourteen subjects(26.0%) were adherer who was keeping aquatic exercise. The reasons of aquatic exercise adherence were improvements of physical and affectional factors. And the major reasons of dropout was an environment factors(65.8%) and second reasons was physical factors(34.2%). Participants of friends(r=.34, p=.014) was significantly associated with the total duration of an aquatic exercise adherence. For these results, the nurse who care to patients with arthritis have to encourage to maintain aquatic exercise within six month after they begin aquatic exercise.