Patients with cervical precancerous lesions were double blindly divided into 2 groups and treated with either Retinamide II (RII) or Riboflavin (VB2) suppository. The suppository containing RII 20mg or VB2 5mg was given intravaginally daily for 100 days, divided into 2 courses. Clinical examination, papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results showed that the disappearance rates of precancerous lesions (DRPL) after the second course of treatment with RII or VB2 were 68.5% and 52.00%, and the overall response rates were 74.29% and 56.0%, respectively. 1 or 2 yrs after treatment, DRPL of the RII, Riboflavin and laser groups did not show significant difference (P > 0.05). The statistically significant differences were among the RII, Riboflavin, laser groups and antiphlogistic treatment group (P < 0.01). The results indicate that local application of RII and Riboflavin may serve as chemopreventive agents for cervical cancer.