Dilated cardiomyopathy can be idiopathic or be caused by many potentially treatable conditions. We report a complex case of peripartum heart failure associated with hypothyroidism and hypoparathyroidism. Myocardial biopsy suggested that hypothyroidism was the main cause for the dilated pattern, but hypocalcemia played a critical role in acute decompensation of heart failure during hospitalization. After a long and clinically complicated hospital stay, correction of hypothyroidism and hypocalcemia resulted in near-normal cardiac function.