Callicebus moloch occurs in Brazilian Amazonia south of the Rio Amazonas in the States of Pará and Mato Grosso. In Pará, it occurs from the west bank of Rio Tocantins/Araguaia west as far as the east bank of Rio Tapajós, south as far as Ilha do Bananal, north of the confluence of Rio das Mortes with the Rio Araguaia; in Mato Grosso, it ranges as far west as Rio Juruena, including the headwaters of the Rio Xingú (M. G. M. van Roosmalen collected a specimen shot by a Waurá Indian hunter along Rio Von den Steinen). In the north-western part of its range, the species is parapatric with C. hoffmannsi along the lower Rio Tapajós, and in the south-western corner of its range it is parapatric with C. cinerascens along the upper Rio Juruena. May have a patchy distribution within its range (Ferrari et al. 2007).