Blood serum neopterin, high sensitivity C-reactive protein (hsCRP), total homocysteine, pyridoxal-5-phosphatc ( P-5-P) and total phospholipid concentrations have been examined in 30 healthy individuals as well as in patients with coronary artery disease (CAD) verified by coronary angiography (43 patients with 1-artery disease, 24 patients with 2-or 3-artery disease, 17 patients with restenosis) before percutaneous transluminal coronary angioplasty. We have observed increased mean concentrations of neopterin, hsCRP and homocysteine as well as decreased mean concentration of P-5-P and phospholipids in all groups of CAD patients. The positive correlation between neopterin and hsCRP in all CAD patients (r = 0.536; Ρ <0.01 ) as well as an increased frequency of these indices above the upper limit of normal during the course of CAD (30.1 % in eases with 1-artery disease, 54.2% of cases in 2-or 3-artery disease, 76.5% of cases in restenosis) allow to conclude that inflammation has a pivotal role in the progression of CAD. In restenosis the determination ot neopterin was of more significance than the determination of hsCRP. The combination of a mild increase of neopterin and homocysteine concentrations points to the worst prognosis of CAD, both after percutaneous transluminal coronary angioplasty and coronary bypass, restenosis was most liekly to appear. Mild increase of homocysteine concentration in patients with CAD docts not only indicate possible thickening of arterial wall and narrowing of lumen but also to impaired trans-sulfuration and remethylation pathways of homocysteine metabolism as well as to delayed methylation processes in the organism. A decrease of serum P-5-P concentration, which in all groups of CAD patiens reached about 50% as compared with healthy individuals, points to impairment of all metabolic processes, which require the biologically active form of vitamin B6 for their action. The decrease of mean serum phospholipid concentration in all groups of CAD patients may indicate both, impaired phospholipid biosynthesis due to delayed processes of methylation in the organism and increased loss of phosphatidylcholine necessary for transportation of oxidised low density lipoproteins into macrophages. Therefore the determination of serum phospholipid concentration and phosphatidylcholine concentration, especially, has the same significance in the course of CAD as the determination of total cholesterol, high and low density lipoprotein cholesterol widely used at present.