Purpose: The purpose of this study was to examine their levels of knowledge of the kidney, self-efficacy, and kidney function in pre-dialysis patients with chronic renal insufficiency. Methods: A total of 142 pre-dialysis patients with chronic renal insufficiency were recruited from a nephrology clinic of a hospital in Korea. Participants' knowledge of the kidney, self-efficacy, and kidney function were measured, and the correlations between these factors were computed. Results: The levels of knowledge of the kidney were moderate, with a mean score of $12.30{\pm}5.35$. Knowledge level was significantly correlated with age, education level, occupation, income, physical symptoms, and information resources (p<.05). The mean score for self-efficacy was $6.06{\pm}2.00$. Self-efficacy was significantly associated with patients' age, education level, occupation, income, cigarette use, and information resources (p<.05). The mean score for kidney function was $35.66{\pm}18.68mL/min/1.73m^2$. Kidney function was significantly correlated with use of medications and drinking behavior (p<.05). Knowledge of the kidney was significantly correlated with self-efficacy (r=.31, p<.001), but not with kidney function. There was a significant correlation between self-efficacy and kidney function (r=.30, p<.001). Multiple regression analysis revealed that self-efficacy and drinking behavior accounted for 11% of the variance in kidney function of pre-dialysis patients with chronic renal insufficiency. Conclusion: Nursing interventions are necessary to increase self-efficacy among pre-dialysis patients with chronic renal insufficiency in order to maintain their kidney function.