Objectives: COVID-19 associated coagulopathy and prophylactic anticoagulant therapy (PAT) are ongoing topics globally. Using PAT for anti-inflammatory effect may prevent thromboembolic events (TEEs). The objective of this study was to determine the anti-inflammatory effects of PAT in hospitalized COVID-19 patients. Methods: We conducted a retrospective observational study in a tertiary pandemic hospital. Patients were divided into two categories according to their PAT therapy status (PAT (+) and PAT (-)) and into three categories according to clinical features (mild: group 1; moderate: group: 2; and severe: group 3). We then evaluated laboratory parameters and clinical courses. Results: We included 662 hospitalized COVID-19 patients in this study. Enoxaparin sodium was given to all patients as PAT therapy. TEE was developed in five patients in the PAT (+) group. Pulmonary embolism developed in 3/5 patients and deep venous thrombosis in 2/5 patients. Disseminated intravascular coagulation (DIC) was detected in 54 patients in group 3. No statistically significant difference was found in 28-day mortality, development of DIC rates, intubation rates, and TEEs. Conclusions: The use of PAT in critically ill patients was not effective in reducing C-reactive protein, which is one of the biomarkers of inflammation.