Purpose: The aim of this study was to examine the characteristics of nutrition-related knowledge, dietary habits, and nutrient intakes of alcoholic patients and how nutrition education affects these nutritional behaviors. Methods: Subjects included 37 adult male alcoholic patients who were hospitalized. The nutrition education program consisted of five lessons over a five-week period. An each 80-minute nutrition education program per week was implemented for the alcoholic patients over a five-week period. Both before and after the implementation of nutrition education, their nutrition-related knowledge and dietary habits were assessed and nutrient intakes were investigated. Results: The subjects showed drinking habits of considerably high frequency, a large quantity of alcohol consumption, and preference for soju (a liquor) over beer. They had proper weight, height, and BMI, and came from relatively poor socioeconomic backgrounds with a low-level of self-rated health status and a comparatively high rate of suffering from disease. Mean score of their nutrition-related knowledge and dietary habits was quite low. They consumed less energy, dietary fiber, vitamin C, thiamin, riboflavin, folic acid, Ca, and K, but more Na compared to each Dietary Reference Intake (DRI). After implementing the nutrition education, mean score of nutrition-related knowledge and dietary habits showed significant improvement. In addition, the meeting rate of each DRI of several nutrients was increased significantly, including energy, carbohydrate, dietary fiber, vitamins A, C, and $B_6$, thiamin, riboflavin, niacin, pyridoxine, folic acid, Ca, P, K, Fe, and Zn, while that of Na decreased. Conclusion: The findings of this study indicate that alcoholic patients had various nutritional problems, such as lack of nutrition-related knowledge, bad dietary habits, and insufficient nutrient intakes, however, these problems can be positively modified by implementation of a relatively short-term nutrition education program.