This is a report of six cases of combined orbital cellulitis and infective cavernous sinus thrombosis, with a literature review. The average age was 39 years, four were male and two were intravenous drug users. All had sinusitis, usually involving more than one sinus. None was diabetic. All patients had headache, fever, reduced ocular motility, lid swelling and proptosis. Other clinical findings were ptosis, chemosis, raised intraocular pressure, reduced acuity, altered mental state, nuchal rigidity, disc pallor and a relative afferent pupillary defect. Contrast enhanced MRI and MRV were the best imaging methods to detect cavernous sinus thrombosis, showing expansion of the cavernous sinus and filling defects. Dilation of the superior ophthalmic vein and narrowing of the intracavernous carotid may also be present. Imaging was negative initially in two patients, but positive when repeated later, which has also been reported in the literature, and may represent the natural progression of the disease. Blood, but not cerebrospinal fluid (CSF), cultures were positive in four cases, with three growing MRSA and one Strep. anginosus. All patients were treated with broad spectrum antibiotics for an average of five weeks, and anticoagulants. None died, but three were left with significant morbidity including reduced ocular motility, loss of vision and an expressive aphasia. This is a useful review of a rare but serious complication of orbital cellulitis. The authors stress the importance of maintaining a high degree of suspicion, particularly when patients with cellulitis develop cranial nerve palsies, systemic toxicity, or progression to bilateral disease.