To explain the marked variation in the reported incidence of how often leukemic cells infiltrate the eye in fatal cases of leukemia, we tested the hypothesis that ocular leukemic infiltration is related to the peripheral leukocyte count during the final hours of life. We reviewed tissue sections, as well as autopsy and clinical records, from 135 patients who had fatal leukemia and had their eyes examined after death at Duke University Medical Center. Infiltrates of leukemic cells were found in the eyes of 42 of 135 patients (31.1%), with the choroid being the most frequently involved site. We detected a significant positive correlation between the ocular leukemic infiltration and an agonal leukocyte count as well as the severity of systemic disease. Differences in the agonal circulating leukocyte count may partly explain variations in the incidence of leukemic infiltrates in different postmortem studies.