Saguinus labiatus occurs in the central and south-central Amazon. It occurs south of the Rio Solimões between the Rios Madeira and Purus. The southernmost part of its range extends along the left bank of the Rio Abunã, crossing the headwaters of the Abunã into the Pando region of northern Bolivia, along both sides of the Rio Acre, and south as far the Río Tahuamanu, a tributary of the Río Orthon, itself; a tributary of the Río Beni (Hershkovitz 1977; Buchanan-Smith et al. 2000). Its range in Peru was reported for the first time by Encarnación and Castro (1990). There it occurs on the basin of the Río Acre, extending south as far as the Río Tahuamanu. It also occurs between the Rios Japurá and Solimões, in the region between the left bank of the Tonantins to beyond the Auatí-Paraná.

Saguinus labiatus labiatus (Brazil, Bolivia, Peru)
This subspecies occurs south of the Rio Solimões between the Rios Madeira (left bank) and Purus, on the right bank (Hershkovitz 1977), south from the Rio Ipixuna. It extends along the left bank of the Rio Madeira and Abunã, to Bolivia, crossing the headwaters of the Rio Abunã, as far south as both sides of the Rio Acre, limited to the north of the Río Tahuamanú, a tributary of the Río Orton (tributary of the Río Beni). Extends into far south-eastern Peru, north of the Rio Tahuamanú (Aquino and Encarnación 1994).

Saguinus labiatus thomasi (Brazil)
The range of Saguinus l. thomasi is well separated from the other two subspecies. It is known from very few specimens. According to Hershkovitz (1977), it occurs between the Rios Japurá and Solimões, throughout the region between the left bank of the Tonantins to beyond the Auatí-Paraná. It may extend west as far as the Rio Içá, but there is no record of it occurring in Colombia. In the east, it is probably restricted to terra firma forest, not inhabiting the extensive inundated forest (várzea) near the confluence of the Rios Japurá and Solimões (Silva Jr. 1988).

Saguinus labiatus rufiventer Brazil
Occurs in the central Amazon, south from the Rio Solimões between the Rios Madeira and Purus to the Rio Ipixuna, an east bank tributary of the Rio Purus. Saguinus l. labiatus occurs south of the Rio Ipixuna.