Chalcosoma atlas is extremely similar in form to C. caucasus, which also occurs on the Malaysian peninsula. C. atlas is readily distinguishable from the latter by the shape of the terminal point of the cephalic horn.  In C. atlas, the end of the cephalic horn has a rather broadened, upward curving hook-like section bearing very distinct, raised ridges.  This feature is lacking in C. caucasus.  Also, unlike the case C. caucasus, there is no dorsal spine on the cephalic horn of C. atlas.  Another feature of note is that the elytra usually more brilliantly bronze in color than in C. caucasus, which generally has a darker, bluish tint.