The object of the study is to determine how officers' behavior affects their victimization. Material for the study derives from judicial files, police files, and personnel records; file material analyzed encompasses 198 cases involving death or injury to 232 victims. Analysis considers the structural conditions of the police operation relevant to the problem of self-protection and the mistakes in officers' behavior likely to jeopardize their well-being. The criminal offenses with the greatest danger to officers' lives are burglaries and traffic offenses. Offenders tend to be male, between 18 and 30 years old, German citizens, and of lower class origin. Most have extensive previous criminal records, have recently undergone a disruption of accustomed patterns in their personal lives, acquired violent associates, weapons, and threatening behavior, and exhibit an increased disposition for violence. As for characteristics of the victims, officers are generally German males with an average age of 32; the risk of being killed increases in the higher age brackets. A crucial factor in self-protection is not, as expected, whether officers have time for planning and preparation in the time between first notice of the incident and confrontation with the offenders. In fact, longer intervention periods appear to increase the danger to the officer. Likewise, a time-span between making contact and the beginning of conflict has little effect. But a time-span between the beginning of conflict and the beginning of violence may save officers' lives. A number of factors suggest that killed or injured officers are not adequately in control of the situation because they started at a disadvantage or because they started at a disadvantage or because they were unable to keep control of an advantageous situation. Seventy-eight case situations are described in detail to illustrate specific self-protection problems. On this basis, 35 patterns of behavior are identified which may endanger officers during police operations. The most prominent among these are failure to take precautions, failure to use available cover, failure to perform a body search, failure to have firearms ready for use, and failure to call in additional personnel. In many cases, wearing a protective vest would probably have prevented officers from being killed or injured. A bibliography, footnotes, and tables are supplied.