This doctoral thesis aims to find evidence of the phenomenon called penal populism in the Brazilian legislative activity, based on the analysis of the justifications of the bills (B s) which tends to increase penalties, presented for the period 2006-2014 in the Chamber of Deputies. This work presents as research problem the investigation of the stated intentions and the reasons why the legislature persists in raising penalty. Why the political insists on increasing penalties? It is hypothesis of this work that the legislator has acted as it has adhered to the penal populism, a phenomenon characterized by speeches and criminal hardening practices, allegedly backed on a homogeneous public clamoring for punishment. This violates the criminal upsurge of principles that derives from the Brazilian constitutional model and invariably bet on the purposes of the sentence recognized as negative general prevention (deterrence) and retribution. So, in the theoretical plan, we have established the theoretical premises for the analysis of B s, (i) indicated five limiting principles of punitive power, (ii) pointed out the theories of the purposes of punishment recognized by the official discourse of penology, and (iii) we exposed the new crime control culture (David Garland), in which the penal populism is inscribed (John Pratt and Julian V. Roberts). In the practical plan, we have analyzed 758 (seven hundred fifty-eight) legislative proposals that, after purification, resulted in 191 (one hundred and ninety-one) that fell within the scope of this research: penalty raising for existing crime. The year 2006 was chosen as the initial term for two reasons. First, allows embracing two terms in the Chamber of Deputies, the 53rd and 54th respectively in the periods 2007-2011 and 2011-2015. Second, it enables the continuity in the production of scientific knowledge on legislative production on penal law, considering research published by the Ministry of Justice, Thinking Series Law No. 32 (Analysis of the justifications for the production of criminal provisions), which covered the study of legislative proposals from 1987 to 2006. The final point at 2014 is justified for two reasons: closing the 54th Legislature Chamber of Deputies (2011 to 2015) and the need to end the data collection phase for this academic paper. The research findings of this scientific study, after quantitative and qualitative analysis of the justifications of 191 B s, identified that: (i) almost half (48.16 percent) of the proposals focus on the deterrent effect of punishment (negative general prevention), the aim of punishment that has characterized the penal populism; (ii) 63.35 percent of B s have made no references to data, studies and statistics related to standard targeted to change, confirming the penal populism process of destatisticalization, a lack of technical knowledge and the supremacy of common sense; (iii) a fifth (20.41 percent) of B s were about crimes against the person, while only 2.09 percent of B s made up the so-called Economic Criminal Law, confirming the selectivity of the legislator; (iv) almost a fifth (19.37 percent) of the proposals indicated responsiveness of the legislator to the media, in which the criminal media repercussion affects the legislature for bringing punitive bill, suggesting a punitive populist behavior of parliamentarians; (v) the B s proved to be diluted among the various most representative political parties, confirming the nonpartisan character of penal populism. The conclusion of the thesis points to the idea that the Brazilian legislator performs irrational legislative criminal policy, flirting with the worldwide phenomenon of penal populism that has characterized contemporary Western democracies. Ignores the principles for criminal law making. Bet on the deterrent function of punishment, whose efficiency has not been proven in history. rather, produced mass incarceration, which is incapable of reducing crime rates.