Three new species of the harvestmen genus Protimesius Roewer 1913 are described from the Amazonian region of Peru. Protimesius amigos n. sp. from Madre de Dios Department may be distinguished by the absence of an anterior prominence on the prosoma and the presence of five pairs of basal large setae on the penis. Protimesius machiguenga n. sp. and P. kakinte n. sp. are described from the Lower Urubamba region of Cusco Department; P. machiguenga n. sp. is similar to P. cirio Villarreal-Manzanilla & Pinto-da-Rocha 2006 and can be distinguished from it by the presence of a conspicuous dorsal prolateral row of tubercles on the male tibia IV; P. kakinte n. sp. is similar to P. amphichelis Roewer 1931 and P. boibumba Villarreal-Manzanilla & Pinto-da-Rocha 2006, but can be separated from these by the development of tubercles on the femur and tibia IV, and by the number of retrolateral tubercles on male femur IV. New records of P. albilineatus (Roewer 1957) from Loreto department in northern Peru are also reported.