Introduction: Upper extremity deep vein thrombosis (UEDVT) is a serious condition associated with fatal complications. It necessitates careful consideration and prompt intervention. Despite the proven effectiveness of point-of-care ultrasonography (POCUS) in detecting UEDVT, it is rarely utilized in the Emergency Department (ED). Purpose: To highlight the role of POCUS in the early diagnosis of UEDVT in the ED. Case Summary: A 65-year-old female, actively undergoing chemotherapy via a right subcutaneous port for known left breast cancer, presented to the ED exhibiting throat irritation, facial swelling, and itchiness. These symptoms surfaced the day after her latest chemotherapy session. She typically experienced similar reactions post-chemotherapy, managed by routine oral antihistamines and steroids, yet this instance persisted despite medication. On examination, she appeared flushed, with a plethoric and erythematous face, accompanied by swelling extending from her neck to the left arm, along with tender left axillary lymph nodes. A POCUS of the left upper arm revealed soft tissue edema, a non-compressible brachial vein, and a hypoechoic floating luminal lesion (Figure 1). Subsequent computed tomography (CT) confirmed upper limb deep venous thrombosis extending into the left subclavian and internal jugular vein, partially non-occlusive in the proximal superior vena cava (Figure 2. A & B). Notably, she had a known contrast allergy, requiring pre-treatment with steroid and diphenhydramine before contrast injection. Based on CT findings, therapeutic enoxaparin was initiated in the ED and patient was admitted under oncology care, subsequently discharged on rivaroxaban. Discussion: Based on previous studies, the reliance on radiologists' availability for vascular imaging to diagnose UEDVT within the ED led to significant delays, extending up to two hours. Notably, the utilization of POCUS by Emergency Physicians resulted in a marked reduction in both diagnosis and intervention times. Furthermore, insights from six prospective studies confirm the accuracy of color-Doppler sonographic imaging in diagnosing UEDVT, showcasing sensitivity ranging between 78% to 100% and specificity from 82% to 100%. This compelling evidence strongly advocates for the broader integration of POCUS in EDs, emphasizing its credibility in enhancing diagnostic accuracy and expediting timely intervention for UEDVT. Applying these findings to this specific patient case, reliance on POCUS could have avoided the risks associated with radiation and contrast exposure Conclusion: Integrating POCUS into the ED's diagnostic protocol for UEDVT enables early detection and intervention, and mitigates risks associated with contrast agents and excessive radiation exposure.