The article reports on the discovery of Juliomys, a rare sigmodontine rodent, in Paraguay. A specimen of the said rodent was obtained while a study on the effects of habitat fragmentation on the Atlantic Forest in the eastern part of the country was being held. The captured rodent was seen to have orange rump and nose and a slightly bicolored tails. It is noted that the foot pads were big and had long whiskers. The discovery led to the conclusion that the Atlantic Forest in Paraguay has significant mammal diversity and needs to be conserved.