<jats:title>Abstract</jats:title><jats:p>From cultures of <jats:italic>Yersinia enterocolitica</jats:italic> H1852, an iron‐complexing and iron‐transporting compound named yersiniabactin was isolated. The structure of the siderophore was determined by a variety of spectroscopic methods, including 2D NMR experiments on the metal‐free ligand as well as its gallium complex. The metal‐free ligand, derivatives, as well as iron and gallium complexes were examined by high‐resolution FAB‐MS, API‐MS, API‐MS/MS and GC‐MS. The novel siderophore contains a benzene and a thiazolidine ring, as well as two thiazoline rings (Figure 1). Its stereochemistry is noteworthy for the presence of five chiral centers, one of which is considerably epimerized. The compound forms stable complexes with trivalent cations such as ferric iron and gallium.