Background: There is a strong correlation between Atherosclerosis and Antiphospholipid Syndrome (APS) regarding cellular activity (expression of adhesions molecules: ICAM-1, VCAM-1, E-selectins) and humoral activity (presence of oxy-LDL antibodies which crossreact with anticardiolipin antibodies). Aim: To evaluate whether APS is a risk factor for development of atherosclerosis and which of the serological parameters: aCL, anti-B2GP1, LAC is the most important risk factor. Methods: We analyzed 3 groups of patients: 1 group (n=5; 3 F, 2 M) PAPS according Wilson criteria 1999), 2 group (n=8 F) SAPS criteria APS and ARA criteria for SLE, 3 group (n=3 F) SLE. All patients were examined concerning traditional risk factors for atherosclerosis. An atherosclerosis was considered as a presence of carotid lesions showed by Doppler USG examination of carotid arteries. All arteries and veins were evaluated by Doppler examination. Presence of ANA, anti-DNA, aCL, anty-B2GD1, anty-oxy-LDL antibodies were evaluated by ELISA and LAC by Barry and Triplett. Premature results: Traditional risk factors for atherosclerosis were observed the most often in SLE patients, less frequent in SAPS pts. Very small frequency of these factors were observed in PAPS pts. There were no atherogenic lesions in SLE patients. In two SAPS patients atherogenic abnormalities correlated with aCL IgG abs and with deep venous thrombosis. In other SAPS patients atherogenic plaques correlated with presence of anty-B2GP1 and LAC abs and also with venous thrombosis. Out of atherogenic two PAPS pts (1 F, 1 M) one showed correlation between aCLIgG, IgM, anty-B2GP1 antibodies with intensive carotid plaques and venous thrombosis. Conclusion: Presence of APS may point to atherosclerosis. Atherosclerosis early diagnosis and treatment should include examination of APS serological parameters. Precise determination of the most important APS parameters connected with atherosclerosis and thrombosis needs long-term study on bigger sample of patients.