Leptospirosis is a bacterial zoonotic disease with multiple serogroups that infects wildlife and humans alike. Several studies have detected the presence of leptospiral antibodies in captive Neotropical primates, suggesting that they are asymptomatic carriers. However, the presence of antibodies in free‐ranging primates and their potential role as reservoirs for this pathogen is not known. In this study, we used the Microscopic Agglutination Test (MAT) to screen two species of free‐ranging tamarins for the presence of Leptospira antibodies using a panel of 21 serogroups. A total of 56 primates (26 Leontocebus weddelli and 30 Saguinus imperator) were screened at the Estación Biológica Río Los Amigos in Madre de Dios, Peru. MAT results with titres of ≥100 in single samples were considered seropositive. Prevalence ratios (PR) were estimated for age group, sex and host species identity. Overall, 51.8% (29/56) of animals were reactive for at least one Leptospira serogroup. Serogroups were distributed as follows: Iquitos (41.1%), Icterohaemorrhagiae (14.3%), Sejroe (3.6%), Autumnalis (1.8%) and Bataviae (1.8%). No significant differences (p > .05) were found for seropositivity frequencies among categories within assessed variables. These results suggest that free‐ranging L. weddelli and S. imperator might serve as reservoirs for pathogenic Leptospira serogroups. Given increasing human‐wildlife contact, future studies that test for active infection are required to determine potential transmission risks to humans.