Lung cancer is one of the leading causes of cancer-related deaths inthe world, accurate staging of lung cancer is extremely important forpatient management and in clinical research.Chest ultrasound may be usedto locate lung tumors and to assess the extent of tumor infiltration into thevisceral pleura, parietal pleura and chest wall. Also ultrasound can be usedin the detection and sampling of supraclavicular lymph nodes in patientswith suspected lung cancer.Thus the aim of our study is to reveal the addedvalue of transthoracic ultrasound in staging of lung cancer. The study wasperformed in Kasr El-Aini hospital, Chest department, Cairo University, inthe period from April 2012 to April 2013 on 50 patients.All patients weresubjected to complete history taking and clinical examination, plain chest Xray and CT scan of the chest, fiberoptic bronchoscopy, transthoracicultrasonography, metastatic work up and biopsy taking. The results of thestudy found that TTUS has better sensitivity, specificity and diagnosticaccuracy than CT chest in detection of visceral pleura, parietal pleura andchest wall invasion and it is more able to detect the presence of encystationthan CT scan detection with further characterization of it’s type.Assessment of diaphragm mobility as well as the presence ofsupraclavicular lymph node was done. Transthoracic ultrasound could helpin staging of lung cancer and aid chest physicians in determining themodality of treatment in each patient depending on his stage.