Abstract Background The occurrence of gastrointestinal parasites in the sun‐tailed monkey ( Allochrocebus solatus ) at the CIRMF primatology center is unknown. We, therefore, assessed the presence and richness (number of different parasite taxa) of gastrointestinal parasites in a semi‐free‐ranging colony of A. solatus . Methods A total of 46 fecal samples were screened using a modified McMaster technique for fecal egg counts. Results In the 46 samples collected, seven taxa of gastrointestinal parasites, including protozoa and nematodes were identified. The most prevalent parasite was strongyles parasites (98%), followed by Trichuris spp. (72%), Strongyloides spp. (67%) and Entamoeba coli (65%). Balantioides coli (33%), Endolimax nana (25%), and Spirurid eggs (26%) were only found in a minority of the animals. Conclusions This study contributes new host records of gastrointestinal parasites in semi‐free‐ranging A. solatus and highlights the need to investigate the health of this species and implement proper precautions in the management of this colony.