Objective — to compare vein wall damage after 810 nm and 1885 nm laser ablation by using of macro- and microscopic examination. Material and methods. There were two series of experiments in vitro using venous segments with a length of 6 cm. Series 1 consisted of 5 venous segments exposed to 810 nm laser coagulation, series 2—5 segments exposed to 1885 nm laser ablation. Laser power was 3.4 W, velocity — 0.6 mm/sec. Macro- and microscopic changes in vein walls were compared in both series (40-fold magnification). Results. Laser coagulation with a wavelength of 810 nm was followed by vein diameter reduction by 14%. Intimal damage was predominantly observed at the point of contact with the laser tip. Laser coagulation with a wavelength of 1885 nm resulted vein diameter reduction by 24%. Swelling of the entire venous wall, vacuolization and vein wall perforation at the point of contact with the laser tip were observed. Conclusion. Laser coagulation with a wavelength of 1885 nm and minimal power (3.4 W) results severe injury of the entire venous wall. Laser ablation with a wavelength of 810 nm and similar other parameters causes just insignificant intimal damage that is not sufficient for subsequent vein obliteration.