The CO2 laser proved to be a vital tool in the development of conservative therapy for the treatment of CIN in the 1980s. In conjunction with colposcopy, the laser has allowed many women to achieve the security of identified and treated CIN with the freedom to live their lives normally, including the achievement of pregnancies. The laser may be used either in the ablative (vaporization) or the cutting mode. This flexibility allows patients with unsatisfactory as well as satisfactory colposcopy to be managed. The results of treatment are universally excellent, with clearance rates of 96% being reported. Complications are rare both in the short and long term, most patients returning fully to normal activities within 4 weeks of therapy. Although the laser is being superceded to some extent by the advent of the loop diathermy technique, it will for years to come represent a valuable and useful tool in the treatment of CIN.