Because pulmonary thromboembolism (PTE) has an inherent high risk of sudden and unexpected death, this condition is a classic entity in forensic casework. The purpose of this study was to elucidate the characteristics surrounding deaths from PTE. We conducted a retrospective study from 2010 to 2019 at the Department of Forensic Medicine in Aarhus, Denmark. We recorded demographic characteristics, risk factors, comorbidities, and autopsy findings, including BMI. Furthermore, we contextualized the role of forensic autopsy in terms of determining the correct cause of death (COD).Among the 3,572 autopsies, 58 had PTE as the main COD (1.6%), whereas only 0.3% of the deaths in the Danish COD registry were attributed to PTE in the same period. The decedents had a mean age of 52 years (range 19–87), and although the majority had preexisting comorbidities, approximately one-third died suddenly and unexpectedly. Additionally, more than half (35/58) of the decedents died in an out-of-hospital setting, and only a few of these (6/35) reported symptoms prior to death, underscoring the insidiousness of the condition. We identified a mean BMI of 32.7 among the decedents, with more than half of them (30/58) having a BMI ≥ 30.In conclusion, obesity is a major risk factor for fatal PTE. The blurred clinical presentation of PTE underscores the importance of an autopsy to determine the correct COD, and with an increased autopsy rate, the true prevalence may well be higher.