The aim of the current study was to investigate whether the combination between mean platelet volume (MPV) and platelet distribution width (PDW) may improve the prognostic information in the prediction of prevalence and extent of coronary artery disease (CAD). We measured MPV and PDW in 2330 consecutive patients undergoing coronary angiography. Significant CAD was defined as stenosis more than 50% in at least one coronary vessel. We additionally measured carotid intima-media thickness (IMT) in 359 patients. Patients were grouped according to the median value of MPV (10.8fl) and PDW (13fl): Group 1 (MPV and PDW < 50th percentile; n = 958); Group 2 (MPV or PDW ≥50th percentile; n = 288); Group 3 (MPW and PDW ≥ 50th percentile; n = 1055). Patients in Group 3 were older (P < 0.001) with larger prevalence of diabetes (P = 0.024). Combined MPV-PWD was significantly associated with baseline glycemia (P < 0.001) and red blood cell count (P < 0.0001), but inversely related to platelet count (P < 0.0001). Combined MPV-PDW was inversely associated with the presence of thrombus, but directly related to the prevalence of chronic occlusion and worse TIMI flow. However, combined MPV-MPV was not associated with the prevalence of CAD [odds ratio (OR) (95% confidence interval (CI) = 0.99 (0.90-1.09), P = 0.87; adjusted OR (95%CI) = 0.95 (0.85-1.05), P = 0.3], or severe CAD [OR (95%CI) = 1.05 (0.95-1.16), P = 0.3; adjusted OR (95% CI) = 0.97 (0.87-1.08), P = 0.63]. No relationship was observed between IMT and the combination of PDW and MPW. This study showed that the combined information on MPV and PDW is not related to the extent of CAD and carotid IMT. Thus, both MPV and PDW can not be considered as a risk factor for CAD.