Dogs are common in Tonga, where they exist in a close relationship with humans as pets and guard dogs and often are free-roaming due to limited property fencing and the need to scavenge for food. Little is known about the health status of these dogs and the type and level of pathogens carried by them. In this study, blood and fecal samples were analyzed to identify the presence of endoparasites and determine packed cell volume (PCV) values for dogs in Tonga. The current data deficit in this area made it necessary to develop a methodology and collect preliminary data to assist with future research in Tonga. Fecal analysis revealed hookworm in 73% of dogs, primarily those 4–12 mo old. Hematologic evaluation revealed low to borderline low PCV in 87% of dogs. The zoonotic nature of some of the pathogens identified poses a public health risk, with a particular risk for children.