We have grown AlN on MnO (111) substrates with pulsed laser deposition (PLD) and characterized their structural properties using various techniques. We have found that hexagonal AlN successfully grows epitaxially on MnO with the use of PLD. Grazing incidence-angle X-ray diffraction (GIXD) measurements have revealed that the epitaxial relationship between MnO and AlN is [0001](AlN)//[111](MnO) and [11-20](AlN)//[1-10](MnO), which minimizes the lattice mismatch (0.8%). We have also found that the heterointerface for AlN/MnO is less abrupt than that for AlN/Al2O3 due to the chemical vulnerability of MnO. (C) 2003 Elsevier Science B.V. All rights reserved.