German prosecutors increasingly not only dismiss cases on grounds of lack of evidence (principle of „legality“), but also use their discretional powers to divert cases from the Courts on grounds of little guilt of the defendant (principle of „opportunity“), thus assuming more and more the role of the judge. Our research, using data from 17 youth prosecutors’ offices in North Rhine-Westphalia, shows that both types of decisions follow different sets of rules. Decisions to dismiss cases are based on criteria such as denial of guilt on part of the defendant or lack of witnesses, while decisions to divert cases are more likely in cases of small damage, not more than one offence committed, or no prior record. However, in applying diversionary decisions, prosecutors also use „extra-legal“ criteria such as defendants’ nationality or unemployment. Further analyses reveal differences between the prosecutors’ offices with respect to the frequency of dismissals and diversionary decisions, all else being equal, as well as similarities between the decisions of single prosecutors and those of their colleagues within their own office. Thus, prosecutorial decisions are influenced by the organizational context. Both the use of „extra-legal“ criteria as well as the differences between prosecutors’ offices call for different and more just measures of de-criminalization.