Inflammatory conditions belong to the most important diseases of the orbit. Children and adolescents are mostly affected and the most common cause is secondary pathogen invasion from acute sinusitis. However in adults most cases involve idiopathic orbital inflammation, previously termed pseudotumor orbitae. Clinical presentation may include painful exophthalmus, skin redness and warming, chemosis and disturbed eye motility. The challenge for imaging investigations, mainly a combination of CT scanning and MRI, is to distinguish inflammatory from malignant conditions, to define the extent of lesions and to document possible complications, such as cavernous sinus thrombosis, meningoencephalitis or cerebral abscesses. Serious potential consequences of orbital infections, including loss of vision or death, are still a risk factor and must be averted by avoidance of delays in diagnosis and appropriate clinical management.