The region of the Guiana Shield is extraordinarily rich in biodiversity. Little is known, however, of the biogeography and conservation status of its diverse primate taxa. The aim of this study was to conduct a rapid survey of primate populations in the northeastern-most part of the state of Bolívar, Venezuela, near the border with Guyana. A previous study had indicated that the white-faced saki (Pithecia pithecia), wedge-capped capuchin (Cebus olivaceus), and red howler monkey (Alouatta seniculus) were present in this area. It had also been suggested that black spider monkeys (Ateles paniscus), golden-handed tamarins (Saguinus midas), and night monkeys (Aotus) may be present in this part of the Venezuelan Guayana. Forty-nine sites of the Río Cuyuní basin were surveyed. Pre-existing forest trails were walked and the Río Cuyuní was also censused by boat. Interviews with local people at all the sites indicated that the only primates inhabiting this region are A. seniculus, C. olivaceus, and P. pithecia. S. midas is not present (or is extremely rare) in the northeastern part of the state of Bolívar. References to night monkeys may well refer to Potos flavus. The presence of an isolated population of Ateles remains uncertain. Cattle ranching, mining, hunting, logging, and the pet trade are major threats to the primates in this part of Venezuela. Further primate surveys should be conducted in the western Guiana Shield.