The aim of this study was to assess whether body mass index (BMI) was associated with abnormal results of other tests related to metabolic disorders in the periodic health checkup, and determine whether changes in BMI were associated with changes in these other tests. We surveyed 2,392 Japanese male workers, aged 19-59 who have received regular health checkups in 2003 and 2004. During the mandatory workplace health checkup, the following are tested: BMI, systolic and diastolic blood pressure, and the levels of total cholesterol, triglyceride, high density lipoprotein cholesterol, hemoglobin A(1C), aspartate aminotransferase, alanine aminotransferase, and gammaglutamyl transpeptidase. These parameters were measured in 2003 and 2004. The receiver operating characteristic (ROC) curve was used to determine the efficacy of BMI in screening for abnormal results in 2003. The areas under the ROC curves for hypertension, dyslipidemia, diabetes, and liver dysfunction were 0.68-0.89, 0.65-0.67, and 0.51-0.67 for 19-39, 40-49, and 50-59 yr olds, respectively. Multiple regression analysis revealed that changes in BMI were significantly associated with changes in the respective items in one year. The BMI predicts metabolic disorders to a certain extent, especially in younger workers, and BMI monitoring may be a useful indicator of change in other annual health checkup items.