PURPOSE: The purpose of this study was to assess the characteristics of the user of complementary?alternative therapies(CAT) and to identify the important predictive factors associated with them. METHOD: This study included 142 patients attending outpatient rheumatology clinics of D Hospital in Busan between July and August in 2001. The multiple logistic regression model was developed to estimate the likelihood of user or nonuser of CAT. RESULT: The duration of illness and chance score of health locus of control were found to be significant factors through the estimated coefficients of using CAT. Duration of illness is longer and chance score of health locus of control is higher in patients who have used CAT in past than that of nonuser. When the model performance was evaluated by comparing the observed outcome with predicted outcome, the model correctly identified 95% of user of CAT and 31% of nonuser. CONCLUSION: In this survey, duration of illness and chance score of health locus of control are found to be significant factors in predicting utilization of CAT. Nurses who care for rheumatoid arthritis patients should take consideration into health locus of control in planning health education programs.