PURPOSE: To evaluate the changes of venous hemodynamics after the treatment of the primary varicose vein of the lower limbs. METHODS: We retrospectively analyzed 493 lower limbs (221 right and 272 left, 157 male and 336 female) who underwent surgery for the primary varicose veins from September 1994 to May 1999. All patients were evaluated using air-plethysmography (APG) pre-and post-operatively. RESULTS: The prevalent age was 40 to 49-year-old and the male to female ratio was 1:2. Presumed etiological factors included occupations requiring long periods of standing in 94 cases, and pregnancy in 188 female cases. The average duration of illness was 12.9+/-8.2 years. 232 limbs were treated with a method of the greater saphenous vein high ligation (GSV HL) and above knee (AK) stripping with varicosectomy (VS), 38 limbs with GSV HL and total stripping and VS, 101 with short saphenous vein HL and VS, 100 with external banding valvuloplasty of GSV and VS, 5 with external banding valvuloplasty of GSV only, 10 with Linton's operation, 6 with GSV branch ligation and VS, and sclerotherapy in 9. The reduction rate of venous volume (VV) were 13.9+/-6.6 % in GSV stripping group and 20.4+/-18.2% in GSV valvuloplasty group. The reduction rate of venous filling index (VFI) were 53.6+/-31.0% in GSV stripping group and 58.9+/-33.7% in GSV valvuloplasty group. The increasing rate of ejection fraction (EF) were 26.9+/-41.1% in GSV stripping group and 21.1+/- 32.2% in GSV valvuloplasty group. The reduction rate of ambulatory venous pressure (AVP) were 4.4+/-128% in GSV stripping group and 22.7+/-73.3% in GSV valvuloplasty group. CONCLUSION: In patients with primary varicose vein of the lower limbs, APG could be a useful method for the documentation of hemodynamic improvement by showing decrease in VV, VFI, AVP and increase in EF.