Extended-release calcifediol (ERC) 30 µg capsules were recently approved as Rayaldee® by the United States Food and Drug Administration (FDA) for the treatment of secondary hyperparathyroidism (SHPT) in adults with stage 3-4 (not 5) chronic kidney disease (CKD) and vitamin D insufficiency (serum total 25-hydroxyvitamin D < 30 ng/mL). Calcifediol is 25-hydroxyvitamin D3, a prohormone of calcitriol (1,25-dihydroxyvitamin D3), the endogenous active vitamin D hormone. ERC capsules have a lipophilic fill which gradually releases calcifediol, corrects vitamin D insufficiency and increases serum calcitriol and thereby suppresses production of parathyroid hormone (PTH) in CKD patients without perturbing normal vitamin D and mineral metabolism. Areas covered: This review focuses on the chemical, pharmacokinetic, pharmacodynamic and clinical profiles of ERC and describes the product's utility relative to other current treatment options for SHPT. Expert commentary: Randomized clinical trials (RCTs) have demonstrated that nutritional vitamin D is ineffective for treating SHPT whereas vitamin D receptor activators can correct elevated PTH but with increased risk of hypercalcemia and hyperphosphatemia. ERC offers healthcare professionals a new treatment option that has been demonstrated in RCTs to be safe and effective for controlling SHPT without meaningfully increasing serum concentrations of calcium or phosphorus.