Vitamin D may have prognostic value in cardiovascular disease (CVD) patients and, in addition to conventional biomarkers, could be a valuable tool for disease management. The aim of this study was to assess the association of vitamin D status in patients with acute coronary syndrome (ACS) and to evaluate its prognostic utility. The levels of 25(OH) vitamin D were correlated with troponin T hs. Forty-eight consecutive outpatients (40 Caucasian and 8 Asian) aged between 40 and 70 years (mean 61.5, range 43-77 years) were enrolled in the study. All patients were admitted to the Emergency Department with chest pain and suspected ACS. The main exclusion criteria were age <18 years, kidney failure, onco-haematological disease, hypo-hyperparathyroidism, hypo/hyperthyroidism, osteoporosis, treatment with bisphosphonate or 25(OH) vitamin D supplementation. Of the 48 subjects included in the study, thoracic pain symptoms were described in 12 patients with unstable angina (UA) and in 6 patients with ST elevation myocardial infarction (STEMI) and in 30 patients with non-ST-elevation myocardial infarction (NSTEMI). Low 25(OH) vitamin D levels correlated with the presence of ACS (p< 0.02) and inversely correlated with Troponin T hs (TnT hs) levels (p< 0.03). The determination of 25(OH) vitamin D levels in combination with TnT hs could improve the research for possible underlying conditions, and these should be managed meticulously according to current guidelines.