Acute pulmonary embolism (PE) is a common, emergent condition and may affect a large number of patients. Copeptin has been indicated to be a sensitive biomarker of arginine vasopressin release, and has diagnostic and prognostic value in various clinical conditions. Genetic mutations are considerable components of thrombophilic diseases, and factor II gene G20210A, (FII20210A), factor V Leiden (FVL, G1691A) and methylenetetrahydrofolate reductase gene C677T (MTHFR677T) single nucleotide polymorphisms are the most common mutations of thrombophilic diseases. In this study, serum copeptin levels were determined in patients with PE and healthy controls, and the results were discussed. The prevalence of some commonly seen thrombophilic mutations was also evaluated in patients with PE. The study included 32 patients (18 male, 14 female) with PE and 24 (13 male, 11 female) age- and gender-matched healthy controls. A significant difference in serum copeptin levels was determined between the patient and control groups (8.58 +/- 4.42 and 4.07 +/- 1.02 pmol/L, respectively). Heterozygous mutant genotype for FII20210A and heterozygous mutant genotype for FVL were observed in 3.1 and 9.4% of patients, respectively. Mutant genotype of 49% was determined for MTHFR677T mutations. It was concluded that copeptin may have diagnostic value for PE.