A 22-week-old 21-kg female Bernese Mountain Dog ingested a topical antipsoriatic preparation containing the synthetic vitamin D analog tacalcitol. The dog died after a history of lethargy, recumbency, paresis of the hindlimbs, increased rectal temperature, dyspnea, and hematemesis. Histologic examination revealed metastatic calcification in the kidneys, lungs, myocardium, brain, stomach, and tear glands. The appearance of soft tissue mineralization in multiple organs is consistent with hypercalcemia derived from excessive vitamin D uptake. Oral toxicity studies for tacalcitol in the dog are not available, but the present report emphasizes the extraordinary toxic risk of drugs containing this vitamin D analog to dogs.