This study addresses the question of whether Operation El Dorado Canyon, the April 1986 US air raid on Libya, influenced the pattern of international terrorism in the period that followed. Specifically, the study documents the frequency and severity of acts of international terrorism over a forty-one-month period centered on the date of the raid Findings indicate that the level of activity of Libyan-associated terrorist groups and, after a brief upsurge, the frequency of attacks against U.S. targets both declined after the raid. Whereas the number of acts of international terrorism worldwide was similar for the periods before and after the operation, the postraid period was characterized by a shift from acts of medium and high severity to acts of low severity in violence. Although findings are inconclusive, they are consistent with the view that the raid had a generalized deterrent effect on international terrorism for the period examined.