Instability in circulation, hypoperfusion, hypoxia, and ischemia in pulmonary thromboembolism (PTE) may occur as a result of failure in pulmonary circulation. All these conditions cause inflammation and oxidative stress. We aimed to investigate inflammatory markers, asymmetric dimethylarginine (ADMA) levels, and the oxidant-antioxidant balance in patients with PTE. This study was conducted as a prospective case-control study. Thirty-eight patients with PTE enrolled to the study. Age- and gender-matched 38 healthy subjects without risk factors for pulmonary embolism were selected as control group. Venous blood samples were obtained from the PTE patients during the initial diagnosis and at the first month of treatment and from the control subjects. Interleukine-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), total antioxidant status (TAS), total oxidant status (TOS), and ADMA levels were measured for all the samples. The results of patients and healthy subjects were compared. The mean age of the control group was 51.81 +/- 15.18 years, and the mean age of the patients was 52.90 +/- 18.22 years (p = 0.770). Deep venous thrombosis was present in 68 % of the patients. While we found significant differences between the patient and control groups in terms of IL-6, TAS, TNF-alpha, ADMA and oxidative stress index (OSI) values (p = 0.001, p = 0.011, p = 0.038, p = 0.028, and p = 0.024, respectively), the TOS value was not different between the groups (p = 0.080). The ADMA, TNF-alpha, TAS, TOS, and OSI values of the patients during the initial diagnosis and at the first month of treatment were not different (p > 0.05). The results of this study indicate an increased inflammation, endothelial damage, and oxidative stress in PTE. No difference at the first month of therapy suggests ongoing processes. We consider that these markers may be useful in the diagnosis and follow up of PTE.