Overweight/obesity among adult survivors of childhood SCT has been considered to be predictive of eventual development of metabolic abnormalities. Fatty liver is increasingly recognized as a major cause of liver-related morbidity and mortality in the general population. However, the real incidence of fatty liver in adult survivors of SCT has not been fully elucidated. We determined whether adult survivors are at risk for overweight/obesity, metabolic abnormalities and fatty liver and whether these risks are associated with cranial radiotherapy (CRT) before SCT. Among the 51 patients (30 males), only two male patients were overweight/obese at the last evaluation. On the other hand, 9 male (30%) and 15 female (71%) patients were underweight. Fatty liver was diagnosed in 11 male (37%) and 10 female (48%) patients during the follow-up period, although patients who had fatty liver did not tend to be overweight/obese. Significantly more patients who received CRT before SCT developed fatty liver with insulin resistance than those who did not (P<0.05). Even patients who are not overweight/obese may develop fatty liver and metabolic abnormalities. We recommend that healthcare professionals recognize these risks and give life-long attention to detecting, preventing and treating late complications after SCT.