This study was designed to investigate the association between the period of engraftment and the nutritional status of patient`s undergoing bone marrow transplantation for acute myelogenous leukemia (AML). Nutritional status was evaluated by body mass index (BMI), percentage of ideal body weight (PIBW), percentage of weight loss, and serum albumin, total protein (T protein), hemoglobin (HGB) and hematocrit (HCT) levels on the day prior to transplantation and on the day of bone marrow transplantation. The periods of engraftment were determined by absolute neutrophil counts (ANC) above 500/㎣ from the day of bone marrow transplantation. The study subjects were 80 patients (55 males, 25 females) with acute myelogenous leukemia admitted to the University Hospital in Seoul. The result of this study is as follows: The nutritional status values of the majority of patients on the day prior to transplantation were in the normal range except for HGB and HCT; however, during hospitalization, all of the levels of the nutritional status values were significantly decreased. The periods of engraftment of the abnormal group according to their BMI, PIBW, HGB and HCT levels on the day of bone marrow transplantation showed no difference when compared to the normal group. However, the periods of engraftment of the abnormal group, according to the percentage of weight loss, albumin, and T protein levels were significantly decreased when compared to the normal group. Therefore, the nutritional status of patients at the time of transplant had a noticeable influence on the periods of engraftment. Our results suggested that nutritional status is a critical factor of engraftment in BMT during pre-transplant and post-transplant. Futhermore, we recommend that the process of nutritional preparation for the transplant should initiate immediately after the transplant decision has been made. (Korean J Community Nutrition 7(4): 578~584, 2002)