State laws require all professionals dealing with children to report suspect abuse, and these professionals must be familiar with the manifestations of accidental and nonaccidental trauma. Despite State mandates, professionals continue to fail to report suspected abuse. Children should be routinely asked about the cause of any injuries they suffer, but they may be too young, frightened, or intimidated to give an accurate history of an injury. Further, in accidental injuries, caretakers may not have witnessed the injury, and a caretaker's delay in seeking help for an injury is a risk factor for abuse. In addition, professionals who believe certain caretakers are unlikely perpetrators of abuse because of age, sex, race, or socioeconomic status may not consider the possibility of abuse. The presence of risk factors involving the child, the caretaker, and the injury increases the possibility that an injury is not accidental. Complete examination of injuries requires determining the location, size, shape, and age of both external and internal injuries. Bruises are the most common injury to the skin of children who are abused and seen in the hospital setting. Although the hand and the belt strap are the most common objects causing injury to abused children seen in the hospital setting, various other instruments are used. Because parents may claim their child bruises more readily than normal, it is important to rule out this possibility by performing clotting studies, including prothrombin time, partial thromboplastin time, platelet count, and complete blood count. A skeletal survey should be considered in the evaluation of children under 2 years of age who have unusual bruises or other signs of abuse. When the abdomen has been injured, a transaminase analysis should be ordered to rule out trauma to the liver. The evaluation of possible Munchausen syndrome by proxy requires careful collection and analysis of data from several sources. The highest morbidity and mortality from abuse are caused by central nervous system injuries. Injuries to the head and face of children are discussed, including shaken baby syndrome, as well as fractures, trauma resulting from folk medicine practice, and thermal injuries. The importance of an autopsy to confirm the cause of death for children who die in the hospital is emphasized. 100 references, 4 tables, 6 figures, and 4 photographs