Internationally, there have been isolated case reports published of children presenting with dilated cardiomyopathy (DCM) in the setting of undiagnosed rickets. Although there has been an increased prevalence of rickets in the United States, there has been only one documented case of associated DCM. At our institution, a hospital database search was conducted from year 1997 to year 2007 to identify patients with confirmed vitamin D deficiency in addition to DCM. Through this search, four exclusively breast-fed African American infants were identified. These infants presented with congestive heart failure secondary to DCM and, at their admission, were found to have laboratory evidence consistent with hypocalcemic rickets. These patients responded dramatically to treatment with vitamin D and calcium, and cardiac function returned to normal within months. Early recognition of vitamin D deficiency was an important factor in these patients’ clinical course. These case reviews present a rare, serious complication of vitamin D-deficient rickets and support evidence for prevention of this nutritional deficiency with vitamin D supplementation in exclusively breast-fed infants.