Background and Aims: Central venous catheters (CVC) are essential in a critical care setting. Thrombosis is one of the very important associated complications that can lead to increased morbidity and mortality. The aim of this study was to find out the incidence of thrombosis in right-sided internal jugular vein (IJV) CVC with the help of color Doppler duplex sonography, its extent, risk factors and clinical impact. Materials and Methods: One hundred consecutive patients having right-sided IJV CVC were included in the study. Color Doppler sonography was performed on the 3 rd and 6 th days after CVC insertion. The size of the thrombus was noted. Presence of diabetes mellitus, hypertension or smoking was noted. Presence of any hypertonic solution and thromboprophylaxis for Deep vein thrombosis (DVT) were also noted. Results: Thrombus was detected in 33 of 100 (33.0%) patients. The incidence in males was 32.86% and in females was 33.33%. Males had a significantly higher incidence of small thrombus (P = 0.05), whereas females had a significantly higher incidence of large thrombus (P = 0.05). DVT thromboprophylaxis was not effective for CVC-related thrombosis. Hypertonic solution, presence of diabetes, hypertension or history of smoking did not increase the risk of thrombosis. Conclusion: CVC-related thrombosis is common and has the potential for serious complications. Females appear to be at a higher risk for larger thrombus formation. DVT thromboprophylaxis does not confer protection for CVC-related thrombosis. Color Doppler duplex sonography provides with an easily available, noninvasive means of detecting a thrombus. More studies are needed to establish a consensus for prophylaxis and treatment of asymptomatic CVC-related thrombosis.