Abstract: Herein, immunoglobulin variable region polypeptides are fused at their N-terminus to a bacterial signal sequence. In one embodiment, the immunoglobulin variable region polypeptides are fused to a tag that that is placed in between a bacteriophage signal sequence and the N-terminus of the immunoglobulin variable region polypeptide. In another embodiment, the N-termini of single-domain antibodies (dAb) are fused to a bacterial signal sequence in the absence of a tag. In a further embodiment, the immunoglobulin variable region antibody fusion proteins are fused to a bacteriophage coat protein and expressed on the surface of bacteriophage providing an efficient way to select small antibody fragments that are labeled and that have high affinity to target ligand.