Background: Mean platelet volume (MPV) is a risk factor for cardiovascular and inflammatory diseases. Aim: To evaluate the association between high MPV and 90-day mortality after an episode of venous thromboembolism (VTE). Material and methods: Retrospective cohort of 594 patients with a median age of 73 years (58% women) with a first episode VTE, included in an institutional Thromboembolic Disease registry between 2014 and 2015. MPV values were obtained from the automated blood cell count measured at the moment of VTE diagnosis. Volumes ? 11 fL were classified as high. All patients were followed for 90 days to assess survival. Results: The main comorbidities were cancer in 221 patients (37 %), sepsis in 172 (29%) and coronary artery disease in 107 (18%). Median MPV was 8 fl (8­9), brain natriuretic peptide 2000 pg/ml (1025­3900) and troponin 40 pg/ml (19.5­75).Overall mortality was 20% (121/594) during the 90 days of follow-up. Thirty three deaths occurred within 7 days and 43 within the first month. The loss of patients from follow-up was 5% (28/594) at 90 days. Mortality among patients with high MP was 36% (23/63). The crude mortality hazard ratio (HR) for high MPV was 2.2 (95% confidence intervals (CI) 1.4­3.5).When adjusted for sepsis, oncological disease, heart disease, kidney failure and surgery, the mortality HR of high MPV was 2.4 (CI95% 1.5­3.9) in the VTE group, 2.3 (CI95% 1.5­4.4) in the deep venous thrombosis group, and 2.9 (CI95% 1.6 ­5.6) in the pulmonary embolism group. Conclusions: High MPV is an independent risk factor for mortality following an episode of VTE.