A study was carried out to determine the effectiveness of the various methods used for treating patients with cervical intraepithelial neoplasia (CIN) detected by the cervicovaginal smear screening programme at the University College Hospital, Ibadan, Nigeria, over a period of five years. During the period, 3 004 patients were screened, of whom 292 (9.7 pc) had smears suggestive of CIN. There were no facilities for colposcopic evaluation of the patients. The patients were treated by cryotherapy, electrocautery, conization of the cervix and hysterectomy. Persistence rates of CIN after cryotherapy and electrocautery were 30.3pc and 31.2pc respectively. There was no evidence of persistent CIN in patients treated with conization or hysterectomy. It is suggested that in the absence of colposcopic guidance, conization or hysterectomy should be used to treat CIN rather than blind application of locally destructive methods like cryotherapy and electrocautery, particularly the higher grades of CIN.