Abstract Dislocation cores influence very significantly plastic behavior of many materials and this is particularly important in intermetallic compounds. We first review the variety of possible core structures and related deformation phenomena and proceed then to show the most important features of dislocation cores that have been found in computer simulations for L12, L10, DO19 and DO22 intermetallic compounds. Unlike in elemental close-packed metals, cores of dislocations in these close-packed intermetallics are frequently non-planar and possess very high Peierls stresses. The first reason is, of course, the crystal structure. For example, both the L10 and DO22 structures are tetragonal and thus the close packed directions in {111} planes are not all equivalent. However, crystallography alone is not capable of explaining the tendency for non-planar core configurations. The analysis presented here shows that, besides the crystallography, the most important parameter controlling the dislocation core structures in intermetallics is the ordering energy. This effect is mediated via its influence on the energy of the stacking fault-like planar defects that are present in the cores and play role in dislocation dissociations.