We conducted a retrospective analysis of the Studies Of Left Ventricular Dysfunction (SOLVD) trials to assess the predictive value of the baseline white blood cell (WBC) count on mortality. Mortality was higher in participants with a baseline WBC count >7,000 compared to those with a baseline WBC ≤7,000 (27% vs 21%, p <0.0001). After controlling for important covariates, each increase in WBC count of 1,000/mm³ was significantly associated with an increased risk of all-cause mortality (relative risk [RR] 1.05, p <0.001). Overall, compared with a baseline WBC count ≤7,000, a baseline WBC count >7,000 was significantly associated with an increased risk of all-cause mortality (RR 1.22, p = 0.001). In participants with ischemic left ventricular (LV) dysfunction, a WBC count >7,000 remained significantly associated with an increased risk of all-cause mortality (RR 1.26, p <0.001), whereas in participants with nonischemic LV dysfunction there was no relation between WBC count and mortality (RR 1.08, p = 0.5). Thus, baseline WBC is an independent predictor of mortality in patients with LV dysfunction, specifically in those with ischemic cardiomyopathy.