Objective-To determine clinical and laboratory findings associated with protein-losing enteropathy, hypomagnesemia, and hypocalcemia in Yorkshire Terriers. Design-Retrospective study. Animals-5 purebred or crossbred Yorkshire Terriers with protein-losing enteropathy, hypomagnesemia, and hypocalcemia. Procedure-Medical records were reviewed for dogs with protein-losing enteropathy, hypomagnesemia, and hypocalcemia. Results-Of 8 dogs with these signs, 5 had Yorkshire Terrier breeding. Common findings were diarrhea, abdominal effusion, leukocytosis, neutrophilia, hypocalcemia (ionized calcium), hypomagnesemia, hypoproteinemia, hypoalbuminemia, hypocholesterolemia, and increased serum activity of aspartate aminotransferase. Conclusions and Clinical Relevance-Yorkshire Terriers are at increased risk for development of protein-losing enteropathy with hypomagnesemia and decreased ionized calcium concentration. Hypomagnesemia and hypocalcemia may have a related pathogenesis involving intestinal loss, malabsorption, and abnormalities of vitamin D and parathyroid hormone metabolism. Serum electrolyte replacement may be required to avoid neurologic and metabolic problems.