The metal content of diaphragm, gastrocnemius, ventricle, and bladder muscles in genetically obese diabetic KK-CA^y and alloxan-diabetic ddY mice was compared with that in prediabetic KK-CA^y and normal ddY mice, because the muscles of the diabetic KK-CA^y mice had morphological abnormalities, such as atrophy, disappearance of Z-band, disturbed myofibrils and swollen sarcoplasmic reticulum. The amounts of calcium (Ca) in gastrocnemius, ventricle and bladder muscles from the prediabetic KK-CA^y mice were significantly 7.7, 98.3, and 36.9% greater, respectively, than those in normal ddY mice. In contrast, the magnesium (Mg) content of the diaphragm, the gastrocnemius, and the ventricle in the prediabetic mice was 8.6, 7.4, and 4.3% lower, respectively, than in the ddY mice. The iron (Fe) content of the diaphragm, gastrocnemius, and ventricle muscles in the prediabetic mice was 29.2, 43.6, and 44.6% greater, respectively, than in the ddY mice. The Ca content in the gastrocnemius muscles of the diabetic KK-CA^y mice and the alloxan-diabetic mice was 19.8 and 11.7% higher, respectively, than in the prediabetic and normal mice. The Ca content of the ventricle muscle was increased only in the alloxan-mice. The gastrocnemius Mg was also 9.0 and 5.5% greater in the KK-CA^y and the alloxan-mice. The Fe content of the diaphragm and the gastrocnemius muscles from the KK-CA^y mice was 27.3 and 23.2% greater, respectively, than in the prediabetic mice. The zinc (Zn) content of the gastrocnemius and the bladder was 16.4 and 18.0% higher, but the ventricle Zn was 13.4% lower, respectively, than in the prediabetic control. The changes in metal content induced by the diabetic state may be related to the morphological abnormalities.