Background: We investigated the ability of the platelet-to-hemoglobin ratio (PHR) to predict mortality and disease severity in patients with acute pulmonary embolism (APE). Materials & methods: The severity of APE was classified as massive (high risk), submassive (intermediate risk) or nonmassive (low risk). PHR is defined as platelet count/hemoglobin count. Results: PHR was significantly higher in patients with massive APE, and this elevation showed a gradual increase from the nonmassive group to the massive group (p < 0.001). In-hospital and 1-month mortality were higher in patients with high PHR values. PHR was an independent risk factor for the development of massive APE (odds ratio: 1.014; 95% CI: 1.011–1.017; p = 0.009). Conclusion: PHR values predicted massive APE and were an independent predictor of mortality in APE.