Objective : In hospital, deep vein thrombosis (DVT) increases the morbidity and mortality in patients with acute medical illness. DVT prophylaxis is well known to be effective in preventing venous thromoembolism (VTE). However, its use remains suboptimal. The objective of this study was to evaluate the impact of quality improvement project on adherence with VTE prophylaxis guidelines and on the incidence of hospital-acquired VTEs in medical patients. Methods : The study was conducted at Saudi Aramco Medical Services Organization from June 2008 to August 2009. Quality improvement strategies included education of physicians, the development of a protocol, and weekly monitoring of compliance with the recommendations for VTE prophylaxis as included in the multidisciplinary rounds. A feedback was provided whenever a deviation from the protocol occurs. Results : During the study period, a total of 560 general internal medicine patients met the criteria for VTE prophylaxis. Of those, 513 (91%) patients actually received the recommended VTE prophylaxis. The weekly compliance rate in the initial stage of the intervention was 63% (14 of 22) and increased to an overall rate of 100% (39 of 39) (P = 0.002). Hospital-acquired DVT rate was 0.8 per 1000 discharges in the preintervention period and 0.5 per 1000 discharges in the postintervention period, P = 0.51. However, there was a significant increase in the time-free period of the VTE and we had 11 months with no single DVT. Conclusion : In this study, the use of multiple interventions increased VTE prophylaxis compliance rate.