Thirteen genera of Eucnemidae containing forty species were collected from the Iquitos region in Peru. Nine of the genera are new to the country: Rhagomicrus Fleutiaux, 1902, Adelorhagus Horn, 1890, Adelothyreus Chevrolat, 1867, Microrhagus Dejean, 1833, Dyscharachthis Blackburn, 1900, Heterotaxis Bonvouloir, 1871, Spinifornax Fleutiaux, 1926, Serrifornax Fleutiaux, 1926 and Maelodrus Fleutiaux, 1928. The previous eucnemid record from Peru contained eleven species in ten genera. Only one of the forty species caught, Entomophthalmus americanus Bonvouloir, was previously known and described from the country. Dyscharachthis, Maelodrus and Adelorhagus are recorded from South America for the first time. Many of the collected species seem to favor white-sand forest as their habitat. Possible reasons for this are discussed. A list of eucnemids from Peru is included, containing taxa already recorded from the country and also taxa that are likely to occur there. A key to the Peruvian genera is included.