The aim of this paper is to analyze from an economic perspective the effects of the judicial careers arrangement on the trials’ outcome. The institutional organization of judicial careers follows two distinct ideal systems. One is characterized by the fact that public prosecutor and judge belong to the same professional body, as magistrates, while the other one is characterized by the separation of the judiciary from prosecutors. We model this feature of the judicial system as a continuum variable and explain why this choice can be appropriate. We obtain that a more unified system of judicial careers leads to fewer distortions in the process preceding the trial, while it introduces more distortions during the trial. We find the optimal degree of separation of judicial careers and provide some comparative statics results.