Patients with Ki-1 (CD30)-positive anaplastic large cell lymphoma (ALCL) occasionally have rare circulating lymphoma cells. We report a case of ALCL with a prominent leukemic phase. A 36-year-old man presented with widespread ALCL involving lymph nodes, spleen, pleural fluid, cerebrospinal fluid, and bone marrow. His white blood cell count was 106,000/mm3 with 20% lymphoma cells. The circulating neoplastic cells were large, and had irregular nuclei with multiple small nucleoli, ample cytoplasm, and multiple clear cytoplasmic vacuoles. This case illustrates that ALCL may have a marked leukemic phase composed of large anaplastic cells.