From May 1986 through May 1989, the annual number of patients evaluated for dog-bite injuries in the Los Angeles County Hospital jail ward more than doubled. During this period, the number of annual extremity angiograms increased from two to 42. Forty-six of the 48 angiograms were done to evaluate injuries sustained from police dog bites. Only two angiograms, both negative, were performed to evaluate injuries sustained from nonpolice dog bites. Ten of 48 angiograms (24%) demonstrated significant arterial vascular injuries. A similar incidence has been reported with more common causes of penetrating and blunt trauma (eg, knives, gun shots, and motor vehicle accidents). The majority of injuries (seven of ten) were in the right upper extremity. An absent or decreased pulse was observed in five patients. Three patients had proximity-only injuries. The most common injury was occlusion (six of ten). Three patients required surgical repair. From this study, the first on extremity arterial injuries secondary to dog bites, we conclude that bites can result in significant injury. A careful physical examination and an awareness of the possibility of significant arterial damage in proximity-only trauma will help to eliminate missed arterial injuries.