OBJECTIVES: Patients with seronegative spondyloarthritis (SpA) - psoriatic arthritis (PsA) and ankylosing spondylitis (AS) - have a higher risk of cardiovascular morbidity and mortality. The aim of the present study was to evaluate the incidence and type of dyslipidemia, a potent atherosclerosis risk factor, in SpA patients. MATERIAL AND METHODS: It was a two-center, case-control study. Patients diagnosed with PsA and AS aged 23-60 years, with disease duration < 10 years, were enrolled. The inflammatory activity, serum levels of C-reactive protein (CRP) and lipid profile were evaluated in each patient. In patients > 40 years old, the 10-year risk of fatal cardiovascular disease (CVD), using Systematic Coronary Risk Evaluation (SCORE), was estimated. RESULTS: In total 79 patients with SpA were included in the study, with PsA diagnosed, n = 39 (mean age 45.1 ±9.6 years; 21, 53.9%, women), and with AS diagnosed, n = 40 (age 40.3 ±9.5; 12.3%, women), control group (CG): n = 88 (age 42.3 ±8.1; 42, 47.7% women). Based on the interview and laboratory tests, dyslipidemia was diagnosed in 19 (47.5%) patients with AS and in 28 (71.8%) patients with PsA. Most patients had hypercholesterolemia or mixed hyperlipidemia. Types of dyslipidemia were similar. In SpA patients (PsA and AS), the level of triglycerides (TG) and atherogenic index (AI) were significantly higher than in the CG, respectively TG in SpA: 116 (83-156) and in the CG: 91.2 (72.6-134.6) mg/dl, p = 0.0182; AI in SpA: 3.77 ±1.26 and in the CG: 2.58 ±1.27, p < 0.0001.The low-density cholesterol (LDL) level was significantly lower in SpA patients than in the CG, SpA: 109.1 ±29.4 vs. CG: 125.2 ±35.9 mg/dl, p = 0.0023. There was a strong negative correlation between CRP levels and HDL cholesterol levels in patients with PsA, rho = 0.42, p = 0.0132. Mean SCORE values were 2.33% in PsA patients and 2.38% in AS patients, which results in moderate 10-year risk of death from CVD. CONCLUSIONS: In young patients with spondyloarthropathies, inflammatory factors significantly influence dyslipidemia patterns, which result in higher TG and lower LDL cholesterol levels. In patients with PsA, dyslipidemia was diagnosed more often than in patients with AS.