Chasme decora is a species of beetle of the family Scarabaeidae. It is found in South Africa (Western Cape, Northern Cape).
Adults reach a length of about . The head and pronotum are black, while the elytra and abdomen are testaceous-brown. The head is punctulate and clothed with black hairs except on the clypeus. The pronotum is clothed with dense hairs and covered with somewhat closely set orange-yellow, minute scales. The elytra have two longitudinal furrow clothed with minute orange scales which also cover the slightly raised costae. There is a series of long, bristle-like hairs along the outer margin.