Nd2Cu2O5 has been synthesized by solid-state reaction of Nd2O3 and CuO at 1010°C for 4 days. It is thermodynamically stable over a very narrow temperature range, 1002-1012°C. At higher temperatures, it melts incongruently to Nd2CuO4 + liquid. At lower temperatures, it decomposes to give a mixture of Nd2CuO4 and CuO. Nd2Cu2O5 is isostructural with the stable monoclinic polymorph of La2Cu2O5, as confirmed by partial Rietveld refinement of X-ray powder diffraction data, a = 13.728(2) Å, b = 3.6566(2) Å, c = 27.549(3) Å, β = 105.19(1)°, space group C2/c.