A two-year-old male domestic shorthair cat was referred to the Department of Small Animal Medicine andClinical Biology at the Ghent University, Faculty of Veterinary Medicine, Merelbeke, Belgium because oflethargy and anorexia. The cat had severe non-regenerative anemia and marked lymphocytosis. Primary nonregenerativeimmune-mediated hemolytic anemia was diagnosed on the basis of severe hemolytic anemia incombination with a positive osmotic fragility test, a positive Coombs test and the exclusion of underlyingcauses. A bone marrow core biopsy revealed erythroid maturation arrest with mild myelodysplasia. The catresponded quickly to treatment with a blood transfusion and immunosuppressive dosages of prednisolone. Theprednisolone was tapered down and stopped after 5 months. Two years after the initial diagnosis, there wereno signs of clinical relapse.