Despite improvements in antibiotic therapies and surgical techniques, sinusitis still carries a risk of serious and potentially fatal complications. We examined the charts of 82 patients who had been admitted to the University of Mississippi Medical Center between Jan. 1, 1985, and Dec. 31, 1999, for treatment of complications of sinusitis. Of these 82 patients, 43 had orbital complications and 39 had intracranial complications. In this article, we describe our findings in those patients who had intracranial complications (our findings in patients with orbital complications will be reported in a future article). The most common intracranial complication was meningitis; others were epidural abscess, subdural abscess, intracerebral abscess, Pott's puffy tumor, and superior sagittal sinus thrombosis. Most patients with meningitis were treated with drug therapy only; patients with abscesses were generally treated with intravenous antibiotics and drainage of the affected sinus and the abscess. Advancements in antibiotic therapy, endoscopic surgery, imaging studies, and computer-assisted surgery have helped improve outcomes. Management of these patients should be undertaken immediately and is best achieved via a multidisciplinary approach, involving the otolaryngologist, neurosurgeon, radiologist, anesthesiologist, infection disease specialist, pediatrician, internist, and others.