OBJECTIVE: To report a case of acute sinusitis that evolved in association with intraorbital abscess. CASE REPORT: The patient, J.L.F, was a 51-year-old white forklift driver from Ourinhos-SP, but born in Barbosa Ferraz-PR. The patient presented complaining of sneezing, a stuffy nose, and yellowish rhinorrhea 3 days after swimming in a pool. The symptoms evolved to include palpebral edema, fever, and pain in the left eye, followed by headache and vomiting. The physical examination revealed proptosis, chemosis and ptosis in the left eye, and neck stiffness. The laboratory tests revealed leukocytosis with a leftward shift; cerebrospinal fluid analysis revealed a bacterial infection. Orbit computed tomography of the nose and sinuses revealed abscesses in the extra- and intraconal compartment of the left orbit, as well as pansinusitis. Magnetic resonance imaging of the skull revealed laminar empyema in the front left dural fold. The patient was treated with ceftriaxone, oxacillin, and metronidazole then subjected to open-jaw sinusectomy (using a Caldwel-Luck incision) and frontal sinusectomy by Linch incision. The sinuses as well as the extra- and intraconal abscesses were drained. The patient's clinical evolution was unremarkable; he was discharged two weeks after surgery. CONCLUSION: One complication of bacterial sinusitis is an orbital abscess.