Numerous modalities have been used to treat facial scars. Although excellent results can be obtained by high-energy, pulsed carbon dioxide(CO2) laser, significant morbidity exists due to the considerable thermal damage to the skin. CO3 Laser combines the performance of a CO2 system with the safety and convenience of an Er:YAG laser. The CO3 effect is due to a wide range of pulse durations, up to 20 times longer than those delivered by conventional Er:YAG lasers. The result is a thermally tunable laser, with a zone of thermal effect up to 100㎛ in depth. With the CO3 laser, the user chooses the correct depth of thermal effect for maximum safety and efficacy. This study was performed to evaluate the effect of the long-pulsed Er:YAG CO3 laserbra-sion in treatment of scars and propose that it can be a effective method to improve cosmetic results. The authors treated 47 cases (8 males and 39 females) including acne scar(n=8), annular atro-phic scar(n=9), posttraumatic scar(n=19), postsurgical scar (n=11) with CO3 laser. Questionaire were completed for clinical assess-ment by the patients and clinicians. Excellent and good results were achieved in 87.3% of scars in clinician's assess-ments and in 78.8% of scars in patient's assessments. In con-clusion, resur-facing with a long-pulsed Er:YAG laser is a safe and very effective treatment modality for facial scars.