The first transition metal iodato peroxido complex, K3[V2O2(O2)4(IO3)]•H2O (I), was prepared by crystallization from the KVO3 – KIO3 – H2O2 – H2O – ethanol (HNO3) solution. The dinuclear anion is immediately decomposed in aqueous solution; the 51V NMR spectrum exhibits signals corresponding to [VO(O2)2(H2O)]–, [V2O2(OH)(O2)4]3– and H2VO4– species only. The IR and Raman spectra contain all characteristic bands of the VO(O2)2 group and the coordinated IO3– ligand. Based on the positions of bands assigned to the vibrations of the VO(O2)2 groups a pentagonal pyramidal arrangement around the vanadium atoms can be supposed. The crystal structure was solved from X-ray synchrotron powder data by direct space method and refined by energy minimization in the solid state employing a hybrid PBE0 functional. This crystal and molecular structure, has confirmed the presence of hexacoordinated vanadium atoms and revealed asymmetric dinuclear structure of the [V2O2(O2)4(IO3)]3– ion. The coordination spheres of vanadium atoms are different – the IO3– anion is coordinated only to one vanadium center. A thermal analysis of the complex confirmed the presence of water molecules in the crystal structure and revealed a considerable stability of the dehydrated complex.