Five hundred and seven Lepidoptera species were collected associated with Eucalyptus plantations in Açailândia, Maranhão State, Brazil. From August 1990 to July 1991, once every two weeks, two light traps were set up to collect insects in an Euclyptus camaldulensis and Eucalyptus urophylla plantations in this region. Seven primary pests were captured: Eupseudosoma aberrane Schaus, 1905 and Eupseudosoma involuta Sepp, 1862, (Arctiidae); Glena spp., Oxydia vesulia Cramer, 1779, Thyrinteina leucoceraea Rindge, 1961 (Geometridae); Nystalea nyseus Cramer, 1775 (Notodontidae) and Sarsina violascens Herrich-Schaeffer, 1866 (Lymantriidae). Besides these species, six secondary pests were captured: Automeris illustris Walker, 1665, Automeris sp., Hyperchiria incisa and Hylesia sp. (Saturniidae); Cosmosoma auge Linné, 1767 (Ctenuchidae) and Idalus affínis (Arctiidae).