<jats:p>The catecholate siderophore serratiochelin isolated from an iron deficient culture medium of Serratia marcescens TW was characterized by mass spectrometry and NMR and by GC/MS analysis of the hydrolysis products as 1-(2,3-dihydroxybenzamido)-3-[4 S,5R-2-(2,3-dihydroxyphenyl)- 5-methyl-2-oxazoline-4-carboxamido]propane. The structure of serratiochelin was confirmed by synthesis. The bacterial strain also produces chrysobactin.