OBJECTIVES: The aim of this study was to determine the levels of homocysteine and high-sensitive C-reactive protein (hsCRP) in (1) patients vulgaris without systemic therapy (PV), (2) patients with psoriasis on biological therapy (PV + biological th) and healthy subjects (controls). The severity of the clinical features of psoriasis patients and its relationship with serum homocysteine levels, hsCRP, anthropometric parameters, hematological and biochemical levels were assessed. STUDY DESIGN: case-control study PARTICIPANTS AND METHODS: The study was conducted on 36 patients treated at the Department of Dermatology and Venereology, University Hospital Center Osijek. Clinical assessment of disease activity was performed using the Psoriasis Area Severity Index (PASI). After that, venous blood was used to determine biochemical and hematological parameters and anthropometric measurements were performed. RESULTS: hsCRP levels are higher in psoriatic patients compared to the control group of healthy subjects, regardless of the systemic therapy involved, and are positively correlated with systolic and diastolic pressures, erythrocyte sedimentation rate, and peripheral blood leukocyte count. Homocysteine levels were significantly higher in the PV and PV + biological th groups of patients compared to controls. We observed a positive correlation of homocysteine concentration with age, and a negative correlation with vitamin B12 concentration. Fibrinogen activity was significantly lower in the PV + biological th group compared to the PV group, with a positive correlation with inflammatory parameters. CONCLUSION: Despite the extremely positive therapeutic effect of biological drugs on inflammatory changes in the skin, in the PV + biological th group we still observe higher values of homocysteine and hsCRP, which indicates a sustained increased risk of developing cardiovascular disease. In contrast, fibrinogen activity was reduced and suggested reduced hypercoagulability compared to psoriatic patients without systemic therapy.