The physiological stress suffered by patients with coronary heart disease (CHD) may result in a shift in leukocyte differential toward a decreased percentage of lymphocytes (L%). The purpose of this study was to determine the prognostic value of a low L% in CHD. One hundred forty patients evaluated in our department between 2007 and 2008 were retrospectively reviewed. Thirty-eight patients had primary percutaneous coronary intervention (PCI), and 102 patients had elective PCI. Various statistical analyses were used to examine the association between a low L% or other clinical characteristics and CHD. Univariate analysis showed that low L% was significantly related to ACS compared with stable CHD or control. White blood cell (WBC) count, C-reactive protein (CRP) and left ventricular systolic dysfunction (LVSD) were also correlated with CHD. Multivariate analysis and logistic regression analysis revealed that L%, CRP, WBC count and LVSD were all independently significant risk factors to have predictive value for CHD and 1 year major adverse cardiac events (MACE). A low L% could be used as an independent predictor for ACS on admission and is associated with MACE during clinical follow-up in CHD patients.