Free-roaming dogs, Canis lupus familiaris, can be both a public health and conservation concern because they are a disease reservoir. Between 2010 and 2013, we identified 2,649 dogs in four rural villages in Tanzania. We characterized dog demography and ownership practices and investigated whether vaccination influences dog population dynamics. We found that adult dogs had higher survival than puppies in all villages. We observed a male-biased sex ratio across all age classes and higher adult male dog survival. Within the vaccination villages, vaccinated dogs had a decreased risk of death. However, overall mortality in one non-vaccination village was significantly higher than in the two vaccination villages and other non-vaccination villages. Dogs in poor body condition had lower survival than dogs in ideal body condition in all villages. Sickness and spotted hyaena (Crocuta crocuta) predation were the two main causes of dog death. We found that dog ownership was related to livestock ownership, household size, education, and house type. Thus the number of dogs increases with household wealth. Free-roaming domestic dogs in rural communities exist in the context of their human owners as well as the surrounding wildlife. Our results demonstrate that vaccination alone does not impact domestic dog population dynamics and that they may be mediated by humans. Understanding the role of dogs and their care within these communities is important for planning and implement rabies control measures such as mass dog vaccination.