Misfit dislocations in epitaxially grown layers of GaAs1−xPxwith a lattice constant gradient were examined by weak beam TEM. They are dissociated into partial dislocations and in specimens with (113) growth planes they form networks of extended and contracted nodes on (111) planes. The dissociation corresponds to an intrinsic stacking fault energy of 43 erg/cm2for GaAs0.7P0.3.