We evaluated the relationship between admission white blood cell (WBC) count and in-hospital outcomes in acute coronary syndrome (ACS) patients from the Middle East. Data were analyzed from 7806 consecutive patients with ACS who were divided into 4 groups (G) according to their WBC count (× 109/L; G1: <6.00; G2: 6.00-9.99; G3: 10.00-11.99; G4: ≥12.00). After significant covariate adjustment, those in G4 were 68% more likely to have cardiogenic shock than those in G1 (95% confidence interval [CI]: 1.05-2.68; P = .030) and G2 (odds ratio [OR], 2.02; 95% CI: 1.51-2.71; P < .001). Those in G4 were 2.02 times (95% CI: 1.11-3.67; P = .021) and 65% (95% CI: 1.17-2.32; P = .004) more likely to die in hospital than those in G1 and G2, respectively. Admission WBC count is an independent risk factor for in-hospital cardiogenic shock and mortality, in Middle Eastern patients with ACS. Novel therapeutic agents targeting WBCs in patients with ACS may improve outcomes.