background: recent studies revealed a strong association between vitamin d (vd) status and chronic heart failure (chf). it is now commonly considered that proinflammatory immune response underlies chf development. objective: since vd expresses anti-inflammatory properties, we investigated its impact on cytokines implicated in chf, such as tnfα and il-17, in patients suffering from chf. methods: blood was obtained from forty patients with chf secondary to hypertension and/or coronary heart disease. vd status, il-17 and tnfαlevels were assessed using 25-hydroxy vd3 eia and cytokine elisas. clinical assessment and echocardiography was also performed. results: elderly patients with chf in nis (southeast europe, latitude 43on) exhibited 25-hydroxy vd3 levels below normal. our data identified that patients with chf secondary to hypertension have significantly lower 25-hydroxy vd3, increased tnfα and il-17a levels in comparison to donors with chf secondary to coronary disease. conclusion: this study reveals that even in regions with a lot of sunny days vd deficiency represents a concerning issue. data suggest that impaired vd status contributes to high il-17 and tnfα levels and thereby may support chf development.