BACKGROUND: New treatment regimens have been introduced in the past 20 years, which may influence the short-and long-term prognosis for patients with and without a cancer diagnosis following pulmonary embolism. However, newer studies investigating these trends are lacking. Therefore, we aimed to investigate the 30-and 31-to 365-day mortality following pulmonary embolism. METHODS AND RESULTS: Using the Danish nationwide registries, patients with a diagnosis of pulmonary embolism between 2000 and 2020 were included. Age-and sex-standardized 30-and 31-to 365-day mortality was calculated and stratified by cancer status. In total, 60 614 patients (29.6% with recent cancer; mean age, 68.2 years) were included. The 30-day mortality for patients with no recent cancer decreased from 19.1% (95% CI, 17.9%–20.4%) in 2000 to 7.3% (95% CI, 6.7%–8.0%) in 2018 to 2020 (hazard ratio [HR], 0.36 [95% CI, 0.32–0.40]; P<0.001). The 30-day mortality for patients with recent cancer decreased from 32.2% (95% CI, 28.8%–36.6%) to 14.1% (95% CI, 12.7%–15.5%) (HR, 0.38 [95% CI, 0.33–0.44]; P<0.001). The 31-to 365-day mortality for patients with no recent cancer decreased from 12.5% (95% CI, 11.4%–13.6%) to 9.4% (95% CI, 8.6%–10.2%) (HR, 0.73 [95% CI, 0.64–0.83]; P<0.001).The 31-to 365-day mortality for patients with recent cancer remained stable: 39.4% (95% CI, 35.1%–43.7%) to 38.3% (95% CI, 35.9%–40.6%) (HR, 0.97 [95% CI, 0.84–1.12]; P=0.69). CONCLUSIONS: From 2000 to 2020, improvements were observed in 30-day mortality following pulmonary embolism regard-less of cancer status. For patients with recent cancer, 31-to 365-day mortality did not improve, whereas a minor improvement was observed for patients without recent cancer.