A tabular report and corresponding structures were downloaded for 696 SARS-CoV-2 Mpro entries, deposited in the PDB database between 5th February 2020 and 26th April 2023. Among these, 497 structures were found to contain non-solvent ligands with molecular weight >= 100 Da. An in-house python script was used to check for covalent bonds between protein and ligands, which were present in 333 structures out of 497. Percentages reported in text are derived from the results summarized in Table . The classification of structures in this table has been manually curated. For instance, a structure in which Mpro active site interacts with another protein classified as "apo" required a manual correction. Additionally, some of the submitted structures might not contain all domains of Mpro, i.e. six asymmetric structures with a ligand do not contain the whole dimer within the unit cell. Among the 10 apo structures with non-cyclic symmetry, the distribution of space groups is the following: P1: 3,P21 21 21: 2, P1211: 2, P21212: 2, P43212: 1.