In order to prolong the survival of patients with cervical cancer, adjuvant immunotherapy was undertaken in Japan. The result of two randomized controlled studies using biological response modifiers such as OK-432 or sizofiran are described. The three-year recurrence-free rates of 221 patients in the OK-432 group and 161 patients in the control group were 71.9% and 58.6%, respectively. The intergroup difference was statistically significant. Of all the patients with Stage II or III cancer, time to recurrence and survival rate in 99 patients in the sizofiran group were significantly longer than in 96 patients in the control, evaluated at 5 years. Based on the results of the 2 randomized controlled studies, we conclude that adjuvant immunotherapy is very useful for prolonging the survival of patients with cervical cancer.