We report a case of hypocalcemic heart failure without underlying myocardial disease. Two-dimensional and Doppler echocardiography revealed dilatation and impaired contraction of the left ventricle, but did not show any valvular dysfunction. Cardiac catheterization showed a normal coronary artery, and cardiac muscle biopsy showed morphological changes in mitochondoria and endoplasmic reticulum, which may be due to metabolic changes. This patient was asymptomatic after the serum calcium concentration was normalized.