In a randomized trial concerning 123 women with CIN, 59 were treated with laser conization under colposcope without further hemostatic remedy and 64 with cold knife conization guided by Schiller's iodine dyeing supported by side sutures, vaginal packing and postoperative oral administration of tranexam acid. Follow-up with colposcopy and cytology was done 3 and 12 weeks post-conization and then every 6 months. The average follow-up period was 36 months (28-48). Peroperative bleeding was rather less pronounced in the laser group. Postoperatively, however, bleeding requiring treatment was significantly less common in the laser group (5%) than in the cold knife group (17%). The recurrence rate of CIN was 7% in the laser group and 10% in the knife group. Stenosis of the cervical canal developed in 7% of the patients in the laser group and in 3.5% in the knife group. After 12 weeks the squamocolumnar junction was visible in its full extent in 66% of the laser treated patients compared with 38% of the cold knife treated patients. It is concluded that laser conization is a safe procedure even without hemostatic procedures other than the coagulation abilities of the laser beam itself, as used in this work.