Introduction. Recent studies demonstrated that increased neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) are associated with a risk of development and progression of arterial and deep venous thrombosis, representing surrogate markers of endot helial injury, inflammation and prothrombotic state. However, until now the role of NLR and PLR in case of superficial venous thrombosis has not been determined. Aim of the study. To evaluate the diagnostic value of the NLR and PLR in patients with varico se veins of lower limbs complicated by acute superficial venous thrombosis. Materials and methods. Thirty patients with acute superficial venous thrombosis (SVT) confirmed by duplex ultrasound were prospectively included in study group. Thirty sex/age matched patients with varicose veins without thrombosis (VV) were used as controls. On the admission th e NLR and PLR were calculated from full blood count in all patients. The values of D dimer and C reactive protein were determined in SVT group before treatment initiation. Results. Median age of the patients was 60 (25% 75% IQR 55 66) years, 56% were fema le. In the study group thrombosis involved only varicose tributaries in 16 (53,3%) cases and the main saphenous trunk in the remaining. In SVT patients the median values of D dimer and C reactive were 635,0 ng/ml (25% 75% IQR 280 1208) and 9,5 mg/L (25% 75 % IQR 2 45,2). The median values of PLR and NLR both were significantly higher in patients with SVT compared to VV group: 147,2 (25% 75% IQR 119 195) vs 113,5 (25% 75% IQR 91 141) and 3 (25% 75% IQR 2,3 3,7) vs 1,7 (25% 75% IQR 1,5 2,3), respectively (p<0, 01). NLR showed moderate positive correlation with level of D dimer in SVT group: r=0,4 (p<0,05). There were no correlations of PLR and NLR with the level of C reactive protein. A trend to higher values of PLR and NLR in patients with main saphenous trunk involvement was observed (p>0,05). ROC curve analysis demonstrated acceptable role of PLR (area under curve = 0,73) and NLR (area under curve = 0,78) for diagnosis of SVT. Using cut off value of NLR > 2, thrombosis was predicted with sensibility of 87% and specificity of 70%. Conclusions. NLR and PLR are not expensive and universally available laboratory tests that can serve as an adjunct for the diagnosis of superficial vein thrombosis in patients with varicose veins of lower limbs. Further studies are re quired to determine the utility of NLR and PLR for prediction of proximal extension and recurrence of superficial venous thrombosis.