Objectives: This study was conducted to investigate the correlation among nurses’ knowledge, their self-confidence about care for delirium and nursing performance for patients with delirium. Methods: The study subjects are the 203 nurses working at general hospitals. The data were collected using the instruments for knowledge of delirium (47 items), performance (23 items), and self-confidence (15 items). The used statistical analysis were t-test, ANOVA, Pearson’s coefficient and multiple regression analysis. Results: Nursing performance level for patients with delirium was 2.85±0.47, knowledge of delirium nursing 32.15±4.36, and self-confidence in delirium nursing 52.00±17.05. The difference in performance were associated with number of caring experience with delirious patients (during for 1 year) (F=3.22, p=0.024), perceived importance (Caring delirious patient is an important nursing intervention) (F=5.85, p=0.003), necessity of education for delirium (F=5.58, p=0.004), and necessity of manuals for delirium care (t=2.11, p=0.036). The nursing performance for patients with delirium had positive relationship with knowledge of delirium (r=0.30, p=0.000) and self-confidence (r=0.35, p=0.000). Factors related to the nursing performance for patients with delirium were ‘self-confidence in nursing performance for patients with delirium’ (β=0.24, p=0.001), ‘knowledge of delirium’ (β=0.16, p=0.002), and ‘necessity of manuals for delirium care’ (β=0.16, p=0.014). These variables explained 18.5% of the variance in nursing performance for patients with delirium. Conclusions: It is necessary to develop systematic educational program and manual for improving the knowledge, self-confidence and performance for patients with delirium among nurses working at general hospitals.