Background Although preventable, venous thromboembolism remains a common cause of hospital acquired morbidity and mortality. Guidelines, such as the one produced by the American College of Chest Physicians (ACCP), are aimed at reducing hospital associated venous thromboemboli. Unfortunately the majority of studies have revealed inadequate adherence to these guidelines. Objective The objective of this study was to evaluate the use of venous thromboembolism prophylaxis at Cork University Hospital. Setting Cork University Hospital, Wilton, Cork, Ireland. Methods Data from the patient's chart, drug kardex and laboratory results were recorded during April 2010. A Caprini score, a venous thromboembolism risk factor assessment tool, was subsequently calculated for each patient based on data collected. Appropriate prophylaxis was determined after examining data collected, Caprini score and prophylactic regime according to the ACCP 8th edition guidelines. Main outcome measure Primary outcome was to analyse adherence to VTE prophylaxis guidelines. Results A total of 394 patients met the inclusion criteria and were reviewed, of which, 60 % (n = 236) were medical and 37 % (n = 146) were surgical patients. In total 63 % of patients received some form of venous thromboembolism prophylaxis. Furthermore, 54 % of medical and 76 % of surgical patients received prophylaxis. However only 37 % of the patients studied received appropriate thromboprophylaxis according to the ACCP 8th edition guidelines (Geerts et al. in chest 133(6 Suppl):381S-453S, 2008). Additionally 51 % of surgical and 27 % of medical patients received appropriate prophylaxis. Conclusion Data collected from Cork University Hospital revealed poor adherence to international venous thromboembolism prophylaxis guidelines. As stated in the ACCP 8th edition guidelines, every hospital should develop a formal strategy for venous thromboembolism prevention (Geerts et al. in chest 133(6 Suppl):381S-453S, 2008). In order to improve adherence to guidelines, Cork University Hospital should develop, implement and re-evaluate a specific protocol for venous thromboembolism prophylaxis.