Understanding the strategies that primates use to survive in fragmented forest landscapes is vital for constructing informed management plans for specific regions and to enable researchers to start to make generalizations. In a 15-month study, we investigated factors that influenced the status of red-tailed monkeys (Cercopithecus ascanius) and their plant food resources in 20 of the few remaining privately owned forest fragments in Central Uganda. We employed transect methods for vegetation assessments and censuses with a short stop upon sighting redtails to establish demographics and food plants consumed. While the sample involved forests of very different successional stages, forest size was the most important factor influencing both red-tail population size and the number of groups per fragment. Number of food tree species influenced only the number of red-tail groups per fragment. Basal area of food tree species and food tree abundance per fragment were not related to red-tail population size or the number of groups per fragment. Food tree species richness, total number of trees, and basal area of food trees increased significantly with fragment size. Availability of food resources was affected by various factors including habitat area, the nature and intensity of human exploitation, and how fragments were managed. The number of groups and abundance of red-tail monkeys declined when anthropogenic consumptive activities increased. In the future, as these forests are further degraded, the availability of food resources will continue to decline, and thus, the probability that these red-tail populations will survive much longer seems unlikely.