In the early days of the war between Iran and Iraq, reports of the sudden deaths of soldiers who previously had survived a penetrating head injury suggested the possibility that a late complication, traumatic aneurysm (TA), could be the cause of this catastrophe. In response, the authors planned a prospective study to perform cerebral angiography in victims with penetrating head traumas, especially in those who had artillery shells or bone fragments passing through areas of dense vasculature. Thirty-one TAs and arteriovenous fistulas were documented. Not all of the lesions, however, were deemed appropriate for surgical intervention. Six aneurysms (19.4%) healed spontaneously and shrank or disappeared on repeated serial angiograms. The authors present their cases and discuss the incidence of TAs, their natural course and behavior, and the special problems encountered in managing these interesting and potentially fatal complications of penetrating head injuries.