Purpose: This study aimed to evaluate the effectiveness of continuous nutritional education and oral mucositis management on the nutritive status of patients who received hematopoietic stem cell transplantation (HSCT). Methods: After randomly allotting 72 patients who received HSCT to either an experimental group or a control group, intensive and continuous care for preventing malnutrition was conducted in the experimental group while usual routine care was conducted in the control group. The changes of the body scale, blood chemistry profile, oral intake calories, nausea and vomitus, and oral stomatitis scores were measured at three points during their hospitalization using a oral assessment guide and nutrition analysis program: admission, HSCT, and discharge day. The differences between the scores of two groups were analyzed by repeated measures analysis of covariance. Results: The number of total lymphocytes was significantly improved in the experimental group after transplantation (p<.001). Nausea and vomiting score was significantly decreased in the experimental group during the conditioning regimen (p<.001). Conclusion: It was found that continuous nutritional education and oral mucositis control is an effective intervention by improving immune condition. Further investigations concerning direct examination of oral intake with controlling the effect of the chemotherapy are needed to ultimately discern the impact of varying oral nutrition patterns during HSCT.