Background-Hyperparathyroidism and low vitamin D status have been implicated in the pathogenesis of heart failure (HF).We examined the prospective associations between parathyroid hormone (PTH), circulating 25-hydroxyvitamin D, and markers of mineral metabolism and risk of incident HF in older men with and without established cardiovascular disease. Methods and Results-Prospective study of 3731 men aged 60 to 79 years with no prevalent HF followed up for a mean period of 13 years, in whom there were 287 incident HF cases. Elevated PTH (≥55.6 pg/mL; top quarter) was associated with significantly higher risk of incident HF after adjustment for lifestyle characteristics, diabetes mellitus, blood lipids, blood pressure, lung function, heart rate, renal dysfunction, atrial fibrillation, forced expiratory volume in 1 second, and C-reactive protein (hazards ratio, 1.66; 95% confidence interval, 1.30-2.13). The increased risk was seen in both men with and without previous myocardial infarction or stroke (hazards ratio, 1.72; 95% confidence interval, 1.07-2.76; hazards ratio, 1.70; 95% confidence interval, 1.25-2.30, respectively). Elevated PTH was significantly associated with N-terminal probrain natriuretic peptide, a marker of left ventricular wall stress. By contrast, 25-hydroxyvitamin D and other markers of mineral metabolism including serum calcium and phosphate showed no significant association with incident HF after adjustment for age. Conclusions-Elevated PTH, but not 25-hydroxyvitamin D or other markers of mineral metabolism, is associated with increased risk of HF in both older men with and without myocardial infarction/stroke. This increased risk was not explained by its association with known risk factors for HF. Further studies are now needed to elucidate the mechanisms underlying this association. (Circ Heart Fail. 2014;7:732-739.)