Neosanfilippia zoiai, new species of terrestrial Isopod from Ecuador is described. The diagnostic characters between the new species and the only current species of the genus,Neosanfilippia venezuelanaBrian, 1957, are discussed. The relationships between the genusNeosanfilippiaand the genusAmazoniscusLemos de Castro, 1967, are discussed. For scanning electron miscroscopy, specimens were fixed in 70% ethanol, dried by air, coated with gold, and studied in a Cambridge Stereoscan 200.