Even though platelet volume has been supposed to be indicator of platelet activation, contrasting results have been reported on its relationship with the extent of coronary artery disease (CAD). No data have been so far reported on Platelet-Large Cell Ratio (P-LCR). Thus, the aim of the current study was to investigate whether P-LCR is associated with CAD. We measured P-LCR in 1882 consecutive patients undergoing coronary angiography. Significant CAD was defined as stenosis >50% in at least 1 coronary vessel. We additionally measured Carotid Intima-Media Thickness (IMT) in 359 patients. The relationship between P-LCR and platelet aggregation was evaluated by PFA-100 and Multiplate. Patients with higher P-LCR were older (P = 0.038), with larger prevalence of diabetes (P < 0.0001), dilated cardiomyopathy or valvular heart disease (P = 0.004) and less often family history of CAD (P = 0.045), more often on statins (P = 0.002), and diuretics (P = 0.016). P-LCR was significantly associated with baseline glycaemia (P = 0.001) and RBC count (P < 0.001), but inversely related to platelet count (P < 0.0001). P-LCR was not associated with the prevalence of CAD (adjusted P = 0.3) or its severity. In addition, P-LCR was not related to Carotid IMT or platelet aggregation in patients with or without aspirin therapy. This study showed that P-LCR is not related to platelet aggregation, aspirin resistance, the extent of CAD and carotid IMT. Thus, P-LCR can not be considered as a marker of platelet reactivity or a risk factor for CAD.