The present work was designed to study clinical features of the post-thrombotic period and evaluate the influence of various treatment modalities in 254 patients presenting with iliocaval thrombosis. They were examined within 7-80 months (median 39, interquartile range 25-54 months) after a thrombotic episode. The highest frequency of recurrent venous thrombosis was documented in patients who had undergone the implantation of a cava filter followed by those undergoing plication of the inferior vena cava (28%, Fisher's exact test p=0.049) or receiving conservative therapy (25%, exact Fisher's test p=0.029). Persistent oedema and trophic skin lesions occurred in 75, 64, and 55% of the patients treated by implantation of the cava filter, plication of the inferior vena cava, and conservative therapy respectively (ANOVA-based Kruskal-Wallis test, p=0.004). Most patients who underwent endovascular or direct surgical treatment presented with classes C4-C6 of chronic venous diseases. Their occurrence showed a moderate negative correlation with the patients' gender (Spearman's rank correlation coefficient –0.47, p<0.05) and positive correlation with the age (Spearman's rank correlation coefficient 0.31, p<0.05). The frequency of class C3-C6 diseases was not significantly different between the groups of patients with different duration of the follow-up period (Pearson's chi-quadrate test, p=0.47). The overwhelming majority of the patients who refused to wear compression hosiery and bandages or used them irregularly eventually developed severe disturbances of venous drainage. It is concluded that the irregular use of elastic bandages and prophylactic compression hosiery is actually akin to the lack of compression therapy. The patients given surgical or conservative treatment were not significantly different in terms of the quality of life (median test: p=0.68; ANOVA-based Kruskal-Wallis test, p=0.23). The study revealed correlation between the quality of specialized medical care provided to patients with deep vein thrombosis and the severity of manifestations of disturbed venous drainage.