Callie Hevner, a five year old female spayed cocker spaniel, presented to the Cornell University Hospital for Animals (CUHA) on March 18, 2003 for evaluation of signs suggestive of liver disease. Subsequent to extensive workup and evaluation over a one-month period, she represented to CUHA on April 17 with signs of mucosal pallor, lethargy and exercise intolerance, anorexia, and generalized malaise. Physical examination and workup were consistent with immune-mediated hemolytic anemia ("IMHA") and that disease subsequently became the focus of her treatment and care. The purpose of this seminar is to explore the pathogenesis of IMHA, its typical presenting scenario, treatment, and prognosis. Using Callie as a model we shall discuss the nature of this disease, and delve into the variants of presentation and treatment.