The European Chemical Biology Database (ECBD) collects experimental results from biological screening programs performed within the EU-OPENSCREEN platform. There are 3 chemical libraries in ECBD: bioactive, diverse, and academic. The bioactive library contains compounds selected with a strong emphasis on target coverage and selectivity. The diverse library contains compounds with unbiased chemical diversity, designed by five academic computational chemistry groups. In the academic library, compounds are collected from European chemists.