We investigated the association between mean platelet volume (MPV) and risk of all-cause mortality in Chinese patients with ST-Elevation Myocardial Infarction (STEMI). We enrolled 1836 patients with STEMI in Xuanwu Hospital from January 2008 to December 2013. Based on MPV, patients were categorized into the following groups: < 9.5 fL (n = 85), 9.5-11.0 fL (n = 776), 11.1-12.5 fL (n = 811) and >12.5 fL (n = 164), respectively. Mean duration of follow-up was 56.9 months, and 197 patients (10.7%) died during follow-up. All-cause mortality rates were compared between groups. The lowest mortality occurred in patients with MPV between 9.5-11.0 fL, with a multivariable-adjusted hazard ratio (HR) of 1.15(95%CI 0.62-1.50), 1.38(95%CI 1.20-1.68), and 1.72(95%CI 1.41-1.96) in patients with MPV of <.5, 11.1-12.5 and >12.5 fL, respectively. Therefore, increased MPV was associated with all-cause mortality in Chinese patients with STEMI. MPV might be useful as a marker for risk stratification in Chinese patients with STEMI.