The crystal of the titled vanadium(IV/V) complex K3[V2O3(nta)2]ź3H2O (nta denotes nitrilotriacetate) has been synthesized and its structure determined. The unit cell contains two different binuclear vanadium(IV/V) groups. The vanadium(IV/V) ions are coordinated by six atoms and each vanadium(IV/V) ion is located in the sphere of distorted octahedral coordination. In each dimer two vanadium ions are in exact equivalent sites and one free electron is shared equally between the two vanadium ions.