The association between chlamydia pneumonia and coronary artery disease is well documented, however less is known about the correlation between chlamydia pneumonia infection and blood inflammatory markers or lipid levels. In 100 patients with proven coronary artery disease (25 females, 61.0 + 4.0 years old), and 60 healthy volunteer control cases (15 females, 60.6 ±3.4 years old), anti chlamydia pneumonia IgG, blood lipid, C-reactive protein and fibrinogen levels were detected. In cases with coronary artery disease seropositivity for IgG antibodies to chlamydia pneumonia (74% versus 34%, p < 0.0001 ), C-reactive protein (mg / /) (2.8 ±0.6 versus 1.4 ±0.6, p < 0.0001 ), fibrinogen (mg / d/) (317.4 ±38.2 versus 256.2 ±34.5, p < 0.0001 ), triglycéride (mg/dl) (217.5 ±39.0 versus 191.0 + 25.9, p <0.0001), LDL-cholesterol (mg /dl) (126.9+ 19.2 versus 110.6± 19.5, p< 0.0001) levels and total cholesterol / HDL-cholesterol ratio (7.7 ±1.8 versus 4.4 + 1.2, p < 0.0001) were higher but the level of HDL-cholesterol (mg/dl) (26.4±6.7 versus 47.0 ±11.2, p< 0.0001) was lower. The levels of total cholesterol did not differ between the two groups (/? = 0.9). Levels of triglycéride (r = 0.60, p< 0.00001), LDL-cholesterol (r = 0.27, p = 0.0004), C-reactive protein (r = 0.69, p < 0.00001), fibrinogen (r = 0.60, p<0.00001) and total cholesterol /HDLcholesterol ratio (r = 0.74, p< 0.00001) had a direct relation, but the level of HDL-cholesterol had a negative (r = -0.80, p< 0.00001) relation with the seropositivity for chlamydia pneumonia. As a result, seropositivity for IgG antibodies to chlamydia pneumonia is considered as a risk factor for coronary artery disease by its association with the atherogenic lipid profile and procoagulant activity