Current research activities are focussing on a complete understanding of the structure and the behavior of ferromagnetic shape memory alloys (FSMA). The Co-Ni-Al system attracts special attention in the area of FSMA due to certain features such as good oxidation resistance, low density and appreciable ductility at room temperature. The present work studied austenitic single crystals with nominal composition Co₃₈Ni₃₃Al₂₉ (matrix B2-β-phase with precipitates of A1-γ-phase) by means of X-ray Kossel diffraction and EBSD within a scanning electron microscope. The samples were prepared by the Bridgman method and grown in [100] direction. Overlaps of Kossel reflections of two different crystal phases were observed which allowed to determine precisely the orientation relationship as Kurdjumow-Sachs:
(1 1 1)_A1 || (1 1 0)_B2, [-1 1 0]_A1 || [-1 1-1]_B2.
 Moreover, remarkable dark regions (lower backscatter coecient ) between the B2 matrix and the γ-phase were seen using backscattered electrons. On the basis of the Kossel investigations it may be concluded that this structure along the boundary is connected to the measured exact plane orientation relationship (misorientation within a few tenths of a degree) and therefore reveals areas of excellent crystal quality with very low dislocation density.