Antibodies are currently field-deployed as the recognition component of sensors that detect biological threat agents. Antibodies that detect simulants of biothreat agents are also incorporated into biodetection platforms for testing and evaluating new devices and materials. Previously, we developed an anti-botulinum toxin antibody using a powerful genetic technology known as phage display, in which a very large library of immunoglobulin (antibody) genes are expressed on the surface of bacteriophage (bacterial virus) particles. We describe here the isolation of additional recombinant antibodies that bind two simulants of biothreat agents: bacteriophage MS2, and the protein ovalbumin (simulants for viruses and protein toxins, respectively). The phage display method allows the rapid selection of genes encoding specific antibodies out of an enormous population of candidates, and the subsequent production of large amounts of the recombinant antibody in bacterial fermentations. A single anti- MS2 antibody was isolated. The screen for anti-ovalbumin antibodies yielded two independent clones with unique nucleotide and amino acid sequences. The antibodies demonstrated specificity for the molecule against which their selections were targeted. A key feature of the method was the use of a recombinant antigen, cloned MS2 coat protein, for the affinity enrichment of clones in place of the intact bacteriophage target.