The authors should like to contribute to the unsettled problem of the development of varicose venous disease with their own experience. They evaluate parallel the histomorphological observations and certain pathobiochemical changes which can be recognized in exstirpated varicose veins. Fourty five stripped saphenas have been studied. They were divided into two groups: a macroscopically normal and a varicose one. The varicose patients were divided again into two subsamples according to the occurrence or lack of thrombophlebitis in their medical case history. The authors were looking for the appropriate pathobiochemical changes of the vessel walls running parallel to the usual histopathological changes. It seems quite possible that the effect which triggers the development of the disease could be anything which causes hypoxia, alters the energy metabolism of the otherwise bradytrophic vascular tissues. Accumulation of proteoglycans, as well as collagen and elastic fibers in place of the smooth muscle cells may cause a decrease in the elasticity of the veins and may produce favourable conditions to thrombus formation and local inflammation.