Synthesis was carried out, and structure solved for the new dinuclear erbium(III) complex having a composition of Na₄[Er ₂(EDTA)₂(C₂O₄)] · 8H ₂O (where EDTA stands for ethylenediamine-N,N′-tetraacetate). The compound was characterized by IR and UV spectroscopy, mass spectrometry, and X-ray crystallography. In the structure of the compound, erbium(III) has C.N. 8 and a coordination polyhedron shaped as a square antiprism. The EDTA and oxalate ions manifest their characteristic coordination modes: N,O-chelate hexadentate and bridge-cyclic tetradentate, respectively.