PURPOSE: Describe our series of patients with non-traumatic orbital diseases. PATIENTS AND METHODS: A series of patients with non-traumatic orbital diseases seen in Lausanne from 1965 to 1996. RESULTS: Inflammatory conditions and infections were the most frequently observed diseases. Pseudotumors were the most representative. Orbital involvement in systemic diseases (for example Graves' disease), vascular tumors and malformations, as well as orbital involvement in rhinological diseases were also often observed. Orbital cysts, particularly dermoid and epidermoid cysts, and orbital diseases of nervous origin were exceptional. Finally, diseases of the lacrimal gland, metastases, secondary tumors from adjacent structures and diseases of mesenchymal origin were more rare. DISCUSSION: This study also reports the proportion of male and female patients and the percentage of proptosis.