Fatty acid-binding proteins play an inconclusive role in lipid metabolism and cardiometabolic diseases (CMDs) which are closely related with psoriasis. Aim of the study was to investigate the diagnostic value of serum liver fatty acid-binding protein (FABP1) level and associations with disease severity, inflammation or metabolic parameters and influence of systemic treatment in psoriatic patients. The study included thirty-three patients with active plaque-type psoriasis and eleven healthy volunteers. Blood samples were obtained before and after 12 weeks of therapy with methotrexate and acitretin. Serum FABP1 concentrations were analyzed by the enzyme-linked immunosorbent assay. Statistical analysis was performed for correlation of FABP1 with anthropometric, metabolic or inflammatory indices and treatment used. Serum liver-type FABP levels were significantly increased in psoriatic patients compared to the controls (p < 0.001). No statistical correlations between FABP1 and PASI (p = 0.25) was noted, however patients with severe psoriasis had the highest level of FABP1. No significance with metabolic parameters was obtained, beside a positive significant relation with BMI after therapy (p = 0.03). Liver-type FABP significantly correlated with CRP (p = 0.01) and morphotic blood elements. Systemic treatment combined resulted in significant decrease of FABP1 (p = 0.04), regardless of the drug: p = 0.1 in acitretin group, p = 0.3 in methotrexate group. Liver-type FABP might be a novel marker of psoriasis and predictor of clinical response to systemic therapy. FABP1 could be involved in CMDs risk assessment and perhaps link psoriasis with hematological disorders.