This paper presents long-term results of a randomised study of ornidazole as a radiosensitiser in locally advanced carcinoma of the cervix. A total of 76 patients were randomised and followed-up with a median of 85 months. All patients were treated with external and intracavitary irradiation. The 10 year actuarial local control rate was 61% in patients receiving ornidazole, compared with 50% for placebo group. This difference was not statistically significant. Ten year actuarial overall and disease-free survival rates were also similar in the two treatment groups. Although, when analysed by stage, there was a significant advantage in the local control (54% vs 15%; P = 0.044) and disease-free survival rates (37% vs 8%; P = 0.047) in ornidazole group for stage IIIB cases, its implication is obscure because of the small number of patients. In this study moderate and severe complication rates were found to be 30%. These results suggest that ornidazole seems to have relatively weak sensitisation and it may show a possibility of a marginal benefit with unconventional irradiation using relatively large radiation doses. However, the results are insufficient for a real gain in the probability of local tumour control and survival.