Hypervitaminosis D was diagnosed in a giant anteater (Myromecophaga tridactyla) and a large hairy armadillo (Chaetophractus villosus) being fed a commercial insectivore diet. Clinical findings included weight loss, reduced appetite, vomiting, and suspected abdominal discomfort. Hypercalcemia (3.68 and 2.04 mmol/L total and ionized calcium, respectively) was detected in the anteater, and plasma 25(OH)D levels were measured and found to be 808.7 and 379.4 nmol/L for the anteater and armadillo, respectively. Dietary change resulted in a reduction of 25(OH)D levels in both animals and resolution of hypercalcemia in the giant anteater. Dietary analysis of the commercial insectivore food revealed levels of vitamin D₃ higher than the data-sheet values. This case report demonstrates that hypervitaminosis D in Xenarthra can be associated with significant clinical signs.