AbstractAs fragment‐based drug design has become established as a standard component of the drug discovery armory, the design of fragment libraries has evolved according to the practicalities of detection methods, synthetic elaboration, and intended use of the libraries. Through experience, several companies have iteratively designed and redesigned their fragment libraries to these ends, and have reported their findings to aid in future library design. Here, some of these libraries are described and various empirical design considerations are reviewed. Design criteria for future directions in fragment library design are considered, such as targeting of membrane‐bound targets or disruption of protein–protein interactions.This article is categorized under: Computer and Information Science > Chemoinformatics