At a maximum-security forensic hospital over a three-year period, 79 patients (35 percent of all patients) were involved in 157 staff injuries. Staff members' average postinjury absence from work was 85 days, at a cost equivalent to about 2 percent of the hospital's budget. Nursing staff, particularly psychiatric technicians, had the highest injury rate. Male staff were about twice as likely to be injured as female staff. More injuries occurred on the second shift. Patients who injured staff were younger than those who did not. Florid psychotic behavior, nonpsychotic agitation, and the recent use of restraints were the most common prodromal signs.