Acute pulmonary thromboembolism is a common and potentially lethal disease. There is limited information about clinical importance of the delay in pulmonary embolism diagnosis. Between January 2009 and December 2010, consecutive 189 patients with PTE were enrolled to this retrospective study. Varriables including age, sex, educational level, smoking, Wells scores, symptoms, embolism types, clinical and radiological findings were analyzed for delay in diagnosis. Study group consisted of 104 (55%) female and 85 (45%) male patients. The mean age of the group was 57,95 (range 19-88) years. The mean time to presantation or patient delay was 7.9± 15.2 (median 3 days; range, 1-120) days. Diagnostic delay caused by initial misdiagnosis of the health care providers was 0.5± 3,9 (median 0; range 0-45) days. Seventy (37,04%) patients had a delay in diagnosis longer than seven days after onset of symptoms of pulmonary embolism. Current smokers, patients with low Wells scores(≤4) and having non spesific CT pulmonary angiographic findings for PTE at the first admission associated with delay in diagnosis in the present study (p<0.05). Massive type of embolism was associated with mortality (p=0,020). Delay in diagnosis in PTE may increase mortality and massive embolism should be monitored carefully.