The levels of PGC1α (peroxisome proliferator-activated receptor gamma coactivator-1 alpha) have been investigated in plasma samples from patients with cardiovascular diseases (n = 110) including aortic aneurysm (n = 69), aortic stenosis (n = 25), patients without aortal pathology and also from healthy individuals (n = 34). In patients with cardiovascular diseases the PGC1α concentration was higher than in healthy individuals, and tended to decrease with age. Increased concentrations of lactate, total homocysteine and asymmetric dimethylarginine in the blood of examined patients suggested a parallel development of endothelial and secondary mitochondrial dysfunctions. The increase in concentrations of lactate and pyruvate above the reference limits was accompanied by the decrease of PGC1α concentrations.