The evolution of low cycle fatigue damage in copper is studied by in situ micro Laue diffraction. Free standing single crystalline micro-cantilevers with a cross-section of 10 x 10 mu m(2) were loaded in displacement controlled mode with a surface strain amplitude up to 5%. The point to point misorientation and the diffraction peak width as a measure of geometrically necessary dislocation density was analyzed locally during deformation and globally after 0, 1/4, 1/2, 3/4, 1 and multiples up to a maximum of 22 full cycles. Two different behaviors were observed (i) samples geometrically suppressing cross-slip show a steady state deformation pattern with dislocations in a pile-up. (ii) The sample with cross-slip does not reach a steady state with dislocations accumulating at the neutral plane. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.