The article introduces ZINC, a free database of commercially available compounds for virtual screening. The database contains 727,842 molecules, each with 3D structures and biologically relevant protonation states, along with properties such as molecular weight, calculated LogP, and number of rotatable bonds. Each molecule includes vendor and purchasing information, making it ready for docking using popular docking programs. The database supports multiple protonation states and tautomeric forms, and multiple conformations are available for some molecules. ZINC is available for free download in various file formats and includes a web-based query tool for searching, browsing, and creating subsets. The database aims to make virtual screening more accessible to a broad community of structural biologists and medicinal chemists. The article also discusses the methods used to prepare the molecules, the database structure, and provides examples of how users can utilize ZINC for various purposes, such as building libraries of specific compound types, obtaining purchasing information for top-scoring hits, and finding compounds similar to known ligands.The article introduces ZINC, a free database of commercially available compounds for virtual screening. The database contains 727,842 molecules, each with 3D structures and biologically relevant protonation states, along with properties such as molecular weight, calculated LogP, and number of rotatable bonds. Each molecule includes vendor and purchasing information, making it ready for docking using popular docking programs. The database supports multiple protonation states and tautomeric forms, and multiple conformations are available for some molecules. ZINC is available for free download in various file formats and includes a web-based query tool for searching, browsing, and creating subsets. The database aims to make virtual screening more accessible to a broad community of structural biologists and medicinal chemists. The article also discusses the methods used to prepare the molecules, the database structure, and provides examples of how users can utilize ZINC for various purposes, such as building libraries of specific compound types, obtaining purchasing information for top-scoring hits, and finding compounds similar to known ligands.