Aplastic anemia (AA) and pure red cell aplasia (PRCA) are two of the various types of immune-mediated cytopenias that can be associated with large granular lymphocyte (LGL) leukemia. We review the experience on LGL leukemia-associated AA and PRCA in the published literature. In the setting of LGL leukemia, AA is found rarely, while PRCA is frequent. However, the diagnosis of LGL leukemia in the presence of pancytopenia is very challenging. In general, the clinical findings and treatment outcome are similar to the idiopathic or primary forms of AA and PRCA. Serial trials of immunosuppressive agents usually result in relatively durable remissions. In refractory cases, studies using newer immunosuppressive agents active against T cells and natural killer (NK) cells are necessary. There are many similarities in the currently known pathophysiologic mechanisms among these three disorders. As LGL leukemia is underdiagnosed, it is interesting to speculate that perhaps a significant proportion of idiopathic AA and PRCA may be, in fact, secondary to LGL leukemia.