Cold agglutinin induced autoimmune hemolytic anemia is uncommonly associated with leukemia and lymphomas. We present a case of a young Mexican female presenting with a cold agglutinin hemolytic anemia with expression of a rare Pr antigen specificity and an aggressive NK-cell leukemia. Our patient had a rapid fatal course. To our knowledge this is the first reported case of such an association. Am. J. Hematol., 2007. © 2007 Wiley-Liss, Inc.