Our work encompassed 60 patients who were provisionally diagnosed to have mediastinal lesions. Full medical history, clinical examination and radiological investigations were performed. One or more of the following invasive diagnostic procedures were used to reach the histopathologic diagnosis: Percutaneous CT guided biopsy which showed moderate positive results (55.5%). Video assisted thoracoscopic biopsy proved to be a sensitive method in well selected cases. (93.3). Open biopsy is the best diagnostic tool when all the other tools failed, and when complete resection of the lesions is anticipated. It showed 100% positively.