Any criminal system gives the judge some discretion to impose the sentence the convicted offender. Sometimes the defendant revealed that he will continue committing crimes in the future. The response of the law in these cases is often the imposition of a security measure after serving the sentence. Also it is possible to face to the danger of the subject increasing the sanction shaping specific crimes for it, or using generic aggravated or aggravated subtypes. But is it possible that the same judge has the power to increase the sentence because the subject is dangerous? The courts, in few occasions, act affirmatively. The majority doctrine is opposed to this approach. The answer (and justification) is in the purposes of judicial activity in the determination of sentence, within the limits imposed by the principle of prohibition of double assessment and legal reform itself driven by new currents of Criminal Law.