Varicose veins are a frequent, multifactorial disease. Despite its prevalence, the pathophysiological mechanism of varicose veins remains incompletely understood. According to various sources, the key mechanisms of the development of this disease are valvular insufficiency and changes in the venous wall. The fundamental question is whether valvular insufficiency precedes and affects the development of changes in the venous wall, or vice versa. The purpose of this study is to analyze the current state of the problem of studying the mechanisms of development of varicose veins of the lower extremities. This review presents the latest data on etiological, pathophysiological and pathogenetic factors involved in the development of varicose veins. Anatomical, ultrasound, and plethysmographic studies have proven that the presence of valvular insufficiency is often found in patients with varicose veins of the lower extremities. Examination of the venous wall reveals structural remodeling in all three layers, hyperplasia of intimal cells and smooth myocytes. The structures of the extracellular matrix play a special role in changes in the venous wall. Changes in the structure of the veins further deepen the valve insufficiency, starting a vicious circle. In addition, the review examines the role of heredity, increased intraabdominal pressure, hormonal and other etiological and provoking factors of varicose veins.