Summary. Phlebosclerosis is a venous wall degenerative disease which has gained little popularity in the literature due to its uncertain clinical significance. The objective of this review is to evaluate the epidemiology, etiology and clinical significance of phlebosclerosis in lower extremities veins, particularly the effect of preexisting phlebosclerosis of the great saphenous vein on vein graft patency. Medline was searched from inception until November 1, 2019. Reference lists of included studies were scanned. Only articles published after 1949 were included. Two reviewers independently screened titles/abstracts and full-text papers for any study design in relation to phlebosclerosis in lower extremities veins and abstracted data. A total of 16 Cohort studies and one case-control study (3708 participants, mean age 61.8 years, 59.3 % men, and 40.7 % women) were included after screening 317 titles and abstracts, and 80 full-text articles. The incidence of phlebosclerosis ranged from 1.5–9.7 % depending on the radiological features. On the contrary, the incidence of the phlebosclerotic great saphenous vein prior to its use as a vein graft was 26.9–91 % on histological examination. The small saphenous vein was the most common location of phlebosclerosis followed by the great saphenous vein. There is a link between phlebosclerosis and age, venous insufficiency and haemodialysis. As for the vein graft patency seven studies demonstrated a correlation between preexisting phlebosclerosis and vein graft stenosis, whereas three studies failed to prove any association. In conclusion, the radiological incidence of phlebosclerosis depended on the ultrasound findings. Its presence in the great saphenous vein prior to its use as a vein graft is established on histological examination. The small saphenous vein is mainly affected. Risk factors included age, haemodialysis, and venous insufficiency. Preexisting wall thickness of the great saphenous vein graft seemed to affect negatively its patency in bypass surgery.