The aim of this cross-sectional prospective study was investigate whether there is a correlation between age, BMI and severity of chronic venous disease (CVD), evaluated clinically (CEAP classification) and anatomically (extent of the epifascial venous reflux). 213 patients, 65 males (30.5%, mean age 45.1 ± 13.9 years) and 148 females (69.5%, mean age 47.5 ± 13.5 years) were divided into three age categories: 18-40 years (40.8%), 41-74 years (56.3%) and ≥75years (2.8%). BMI was classified as normal weight (18.5 - <25 kg/m(2)), overweight (25 - <30 kg/m(2)) and obesity (≥30 kg/m(2)). Clinical examination of the lower limbs assessed presence and severity of venous signs as included in the CEAP classification. BMI was calculated. Anatomical extent of CVD was described as the number of segments of the superficial and perforating veins with documented reflux by duplex imaging. Median age increased the number of insufficient venous segments (1 insufficient venous segment - median age 41.0 years, 5 insufficient venous segments - median age 51.0 years). The frequency of reflux in the superficial and perforating veins significantly increased with age (p<0.05). A statistically significant correlation was also found between age and the CEAP classification (p<0.01). This was more significant than the correlation between age and number of insufficient venous segments. In the whole group and in women the Spearman's correlation analysis revealed only a weak positive correlation between BMI and reflux in the superficial veins (r=0.145 respectively r=0.264) (p<0.05). No correlation was found in men (r=0.091). Weak positive correlation between BMI and stage of venous insufficiency (CEAP classification) was demonstrated for the whole group of patients (r=0.229, p<0.01), for women (r=0.293, p<0.05) and for men (r=0.245, p<0.01). Multiple linear regression showed age (p<0.0001) and BMI (p=0.049) as significant predictors of clinical grade according to the CEAP classification and the CEAP clinical class (p<0.0001) as a significant predictor of extent of the epifascial venous reflux. The study confirmed the relationship between age, clinical (CEAP clinical class) and pathophysiological (extent of the venous reflux) severity of CVD Older age means an increased number of insufficient venous segments and increased risk of the clinical progression of CVD from varicose veins to chronic venous insufficiency (C(3)-C(6), trophic skin changes and venous ulcers). Our results support the BMI, in term of frequency of venous reflux, as a risk factor in the whole group of patients but only in women but not in men. Multiple linear regression showed BMI together with age as significant predictors of clinical grade of CVD (p<0.05) according to the CEAP classification. As regards the influence of BMI on clinical severity/grade of CVD (CEAP), the results of our study support BMI as an important risk factor.