Libraries of antibody fragments displayed on filamentous phages have proved their value to generate human antibodies against virtually any target. We describe here a simple protocol to make large and diverse libraries based on a single or few frameworks. Diversity is introduced in the third hypervariable loops using degenerate synthetic oligonucleotides and PCR assembly. Because all the antibody fragments isolated from the library will share their framework sequence, their stability and physical properties will be more consistent and customizable than when antibody fragments are isolated from a library prepared from human donors.