The Tenebrionoidea of the Smithsonian Environmental Research Center, Edgewater, Maryland were inventoried over a three year period. Ten families and 49 species were collected: Anthicidae- 1, Ciidae- 2, Melandryidae- 3, Meloidae- 3, Mordellidae- 10, Mycetophagidae- 2, Pyrochroidae- 2, Synchroidae-1, Tenebrionidae- 22, and Tetratomide- 3. Only one of the 49 species collected was non-native.