Suspected lower extremity deep venous thrombosis is a common clinical scenario which providers seek a reliable test to guide management. The importance of confidently making this diagnosis lies in the 50% to 60% risk of pulmonary embolism with untreated deep vein thrombosis and subsequent mortality of 25% to 30%, balanced with the risks of anticoagulation. The ACR Appropriateness Criteria Expert Panel on Vascular Imaging reviews the current literature regarding lower extremity deep venous thrombosis and compared various imaging modalities including ultrasound, MR venography, CT venography, and catheter venography. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.