Today, crystallographic data are more complicated than ever. Even experienced researchers may not always see analytic flaws. To make the lives of authors, referees, readers, and editors just a little bit easier, we would like to advertize a free service set up by the International Union of Crystallography. This is based on a rich set of experience with such data: "Checkcif" thoroughly examines crystallographic data in the CIF format for completeness and consistency, and performs geometry and symmetry checks to detect possible errors of analysis, such as high residual electron densities. Authors who submit manuscripts with structural analyses (to be deposited with either CCDC or FIZ Karlsruhe) are kindly asked to supply the report generated by the checkcif service.