Unusually late onset of cerebrospinal fluid rhinorrhea after head trauma. Two cases of acute meningitis and cerebrospinal fluid rhinorrhea, in which the head trauma responsible occurred 10 and 30 years before, are presented. Intraoperatively, the brain parenchyma was found to be plugged into the fractured anterior fossa. By debridement and duraplasty from an intradural approach, both patients were cured. Several precipitating factors could be responsible for this unusually late reopening of the fistula. The possible accidental causes could be coughing or undetected microtraumas, but in the long run, atrophy of tissues and consequent changes in brain compliance with aging may play a role. 