To know the clinical profile as well as the prognostic significance of elevated levels of parathyroid hormone (PTH) in patients admitted for acute coronary syndrome (ACS). Observational and prospective study of patients admitted for ACS in a single Spanish center during a period of six months. The circulating concentrations of PTH, calcidiol, calcitriol, NT-proBNP, C-reactive protein, cystatinC and fibrinogen were determined within the first 48h at admission. We performed adjusted models to predict death or re-entry for ACS after hospital discharge. A total of 161 patients were recruited (age 67±14 years, 75.2% were men). Forty-one (25.5%) patients had elevated PTH values. During follow-up for a period of 275 person-years, 50 adverse events were recorded. Patients with elevated PTH levels were proportionally more women (21.2 vs. 39.0%) and older (63.3 vs. 77.8 years, both P<.05). Likewise, they presented significantly more cardiovascular risk and a worse prognosis during follow-up (incidence rate ratio 2.64 CI 95%: 1.5-4.6). However, in an adjusted model by the GRACE score, PTH levels were not shown to be an independent risk factor (hazard ratio=1.1; 95% CI: 0.6-2.2), neither other components of the panel. The proportion of patients with elevated levels of PTH admitted for ACS was high. The presence of high PTH levels was associated with an unfavorable clinical profile and a worse outcome during the follow-up, although it was not an independent predictor of poor prognosis.