SPO1 bacteriophage injects its DNA into minicells produced by Bacillus subtilis CU403 divIVB1. The injected DNA is partially degraded to small trichloracetic acid-precipitable material and trichloroacetic acid-soluble material. The injected DNA is not replicated; however, it serves as a template for RNA and protein synthesis. The RNA produced specifically hybridizes to SPO1 DNA, and the amount of RNA hybridized can be reduced by competition with RNA isolated at all stages of the phage cycle from infected nucleate cells of the B. subtilis CU403 divIVB1. An unrelated phage, SPP1, also induces phage-specific RNA in infected minicells. Translation occurs in SPO1-infected minicells resulting in at least eight proteins which have been separated by gel electrophoresis, and two of these proteins have mobilities similar to proteins found only in infected B. subtilis CU403 divIVB1 nucleate cells. A large proportion of the polypeptide material synthesized in infected minicells is very small and heterogeneous in size.