We here describe a new species of Atractus from the Atlantic Forest of Alto Paraná Paraguay. The new species differs from other Atractus by the combination of the following characters: 17 dorsal scale rows without reduction, six supralabial and infralabial scales, only one post-ocular, a uniformly gray dorsum and a whitish belly with iridescent tonalities. The new species of Atractus is known only by the holotype which is a female specimen, and two paratypes. This is the third species of the genus recorded in Paraguay. Given the current status of the Atlantic Forest in Paraguay and in South America, the present species might be classified as highly threatened.