Pulmonary thromboembolism (PE) is found commonly in forensic pathology practice, as it typically causes sudden death. It is attributed to a wide variety of predominantly acquired etiologies. Although likely etiologically multifactorial, some common proximate causes include: surgery, pregnancy, injury, inactivity of any cause, cancer, obesity, or serum hyperviscosity. On occasion, no apparent predisposing condition is identified. In these instances, occult hereditary thrombophilias may play a causal role. Deaths referred to the Office of Chief Medical Examiner (OCME) of New York City between December, 2000 and September, 2003 and due to PE were retrospectively reviewed. Molecular analysis (FRET) was performed on selected cases for three common hereditary thrombophilias: mutations in factor V Leiden (FVL), prothrombin G20210A (PT), and methylenetetrahydrofolate reductase (MTHFR). During the study period, 124 of 15,280 deaths were primarily attributable to PE. Of those, 34 were selected for molecular analysis. One or more mutations were detected in 35% of those, five of which were clearly causally related to death. Given the potential benefits to surviving family members, our data indicate that postmortem molecular testing for the common hereditary thrombophilias is warranted in at least selected cases.