A prospective study of 25 patients with proptosis related to E.N.T. diseases were referred to E.N.T. department, Al- Yarmouk Teaching Hospital during period from Oct. 2000 to Oct. 2001. A complete clinical evaluation of cases had been done by history taking, proper clinical examination, radiological examination, microbiological study, and histopathological examination. Thirteen patients were males and twelve patients were females. The age of them ranged between 4 – 71 years with mean age 37.14 years. The most common associated symptoms and signs with proptosis were nasal obstruction, hyposmia, headache, diplopia, nasal mass and impairment of eyeball movement. The results showed that the proptosis was due to inflammatory lesions of sinonasal region in 64%, malignant tumours in 28% and benign tumours in 8%. The orbital infection complicated acute bacterial sinusitis was the most common inflammatory lesion causing proptosis which formed 24% of all cases followed by fungal sinusitis which formed 20 % of all cases CT scan was very helpful in early diagnosis of the diseases and in detecting the extension of lesions The orbit and its contents are at risk in different types of pathological lesions involving sinonasal region, therefore the proper otorhinol aryngological examination for each patient complains of proptosis is essential and the otorhinolaryngologist play an important role in the diagnosis of diseases that cause proptosis.