Two Nb rat prostatic adenocarcinomas, 13 Pr-12, an autonomous tumor, and 2 Pr-128, an androgen-dependent tumor, were transplanted into groups of congenitally athymic nude mice. The agents used for treatment of these tumors are agents characteristically not used in treatment of prostatic adenocarcinoma in humans. However, these have been efficacious in treating other solid malignancies. Both agents, BCNU and Actinomycin-D, were efficacious in producing tumor regression and in causing at least a temporary decrease in tumor growth. The combination of the Nb rat prostatic adenocarcinoma model and nude mouse is presented as an appropriate system to screen therapeutic agents that have proved efficacious in treatment of other solid malignancies but have not been used in treating prostatic adenocarcinoma.