Gastrointestinal parasites are frequently encountered in captive non-human primates and infestation may have severe consequences on the animal’s health status. Most of these parasites are also transmissible to humans. Nevertheless, little is known about the prevalence and monitoring modalities of gastrointestinal parasitoses in non-human primates housed in zoological institutions and there are currently no guidelines available for their detection and identification. The objective of this study was to identify the main gastrointestinal parasites that may be observed in non-human primates in zoological institutions in France, as well as to develop a decision-making tree to ease their identification. Twenty-four zoological institutions were surveyed, most of which performed fecal examinations routinely on their non-human primates (91.7%). Most institutions used flotation enrichment protocols to detect gastrointestinal parasites (95.2%) and nematodes were the most frequently encountered parasites (73.0%). A total of 252 fecal samples corresponding to 68 different non-human primate species from these institutions were analyzed using sedimentation and flotation protocols. Protozoa (47.3%) were found to be more frequent than helminths (15.6%). Furthermore, old-world monkeys exhibited a higher parasite load (93.6%) than any other non-human primate species category. Compiled data from fecal examinations allowed the development of a decision-making tree and diagnostic atlas to facilitate parasite diagnosis in captive non-human primates.