Patiromer is a novel potassium-binding compound which has recently received FDA approval. This ion exchange resin releases calcium when it binds potassium. We describe the development of hypercalcemia after initiation of patiromer. The calcium levels fell when the drug was stopped but recurred when it was later resumed. Patiromer was again discontinued, and the serum calcium level fell back into the normal range. We believe this patient manifested patiromer-induced hypercalcemia.