Objective: Domestic dogs can maintain health on complete and well-balanced canine plant-based nutrition (K9PBN). Novel insight on health outcomes in dogs consuming K9PBN is of relevance to veterinary professionals and consumers given a growing interest in non-traditional dog foods with perceived health benefits, while considering potential safety concerns. We aimed to investigate nutritional equivalence by measuring clinical health outcomes in adult dogs fed K9PBN over twelve months compared to a meat-based diet at baseline. Animals: Fifteen clinically healthy adult dogs living in households in Los Angeles County, California. Procedures: Prospective cohort study evaluating clinical, hematological, and nutritional parameters in dogs at 0, 6, and 12 months, including complete blood count (CBC), blood chemistry, cardiac biomarkers, plasma amino acids, and serum vitamin concentrations. Results: Clinically healthy, client-owned, adult dogs maintain health, based on physical exams, CBC, serum chemistry, plasma amino acids, serum vitamins, and cardiac biomarkers combined with client-reported observations, when fed commercial K9PBN over a twelve-month period. Clinical Relevance: This study is the most comprehensive and longest known K9PBN investigation to date. It provides clinically important evidence-based nutrition data and new knowledge on outcomes in clinically healthy dogs who maintain health without consumption of animal-derived ingredients. Also, it is of major relevance to One Health paradigms since ingredients produced independent of industrial food animal production are both more sustainable and help to circumvent ethical dilemmas for maintenance of health in domestic dogs.