BACKGROUND AND OBJECTIVE: The diagnostic value of ST-segment deviation detected by ambulatory electrocardiography (AECG) is controversial in identifying coronary artery disease (CAD) referred for coronary angiography (CAG). Recently, many parameters which evaluate CAD can be derived from AECG. Therefore, we aimed to investigate the diagnostic value of AECG in screening CAD referred for CAG when several parameters were combined. METHODS: We studied the 104 chest pain inpatients. All patients received the CAG and AECG. A lumen diameter reduction of >/= 50% was considered CAD according to CAG. The parameters derived from AECG included ST-segment deviation, apnea hypopnea index (AHI), QT interval dispersion (QTd) and heart rate variability (HRV). The diagnostic value of AECG in screening CAD was evaluated. RESULTS: Of the 104 patients, 57 (54.8%) had CAD according to CAG. The sensitivity of ST-segment deviation in screening CAD was 64.9%; the specificity was 89.4%; and the Kappa value was 0.528. The sensitivity of at least three combined parameters including ST-segment deviation, AHI, QTd and HRV was 89.5%; the specificity was 87.2%; and the Kappa value was 0.767. CONCLUSION: AECG is very useful in screening CAD referred for CAG, especially while several parameters including ST-segment deviation, AHI, HRV and QTd are combined.