IT WAS SHOWN in a recent study that the level of the hematocrit in 100 males with acute myocardial infarction was significantly higher than in age-matched controls.1 The purpose of the present study was to extend the observations on the relationship of hematocrit and myocardial infarction to women. Material and Methods The material for this study was obtained from the Touro Infirmary in New Orleans. The records of 120 females with acute myocardial infarction were selected at random from the hospital files. The ages of the patients ranged from 32 to 90 years ( mean, 63 years). The percentage of the patients in various age groups is shown in Figure 1. No patients with diseases known to affect the hematocrit, such as carcinoma, pulmonary disease, uremia, and polycythemia vera, were included in the series. The hematocrits of all patients were determined at the time of admission to the hospital. The