PURPOSE: The purposes of this study were to explore the concept of uncertainty and to examine the relationships among uncertainty, appraisal of uncertainty, depression, anxiety, and perceived health status in patients with atrial fibrillation. METHOD: The study utilized a descriptive correlational survey design using a face to face interview method. A convenience sample of 49 subjects were recruited from K university hospital over 8 months. The data were analyzed by t-test, ANOVA, Pearson correlation and partial correlation analysis. RESULTS: 1) Subjects perceived with moderately high uncertainty(M=65.98); moderate physical health(M=39.80), mental health(M=47.38), and general health(M=2.94); moderate anxiety(M= 44.78); and slightly low depression(M=15.33). 2) There were significant differences in uncertainty by gender and education. 3) Uncertainty and danger appraisal were significantly correlated(r=.32, p=.03) while the uncertainty was not associated with opportunity appraisal. 4) Uncertainty was significantly correlated with mental health(r=-.31, p=.04), anxiety(r=.38, p=.01), and depression(r=37, p=.01). CONCLUSION: This study was the first trial to explore uncertainty and to examine the relationships among its associated factors in Korean patients with atrial fibrillation. Thus, based on the findings of this study, directions for nursing practice and further nursing research for patients with atrial fibrillation were suggested.