Political corruption is defined like misuse public office for private gain. The electoral rules, district magnitude and political system can affect the corruption, because they give incentives to “good” or “bad” behavior in the office. This paper development a bargaining model in a legislature, using the “Ley de Bancadas” in Colombia to know how the intra-party discipline affects the corruption. The main result is that an effective intra-party discipline cannot work whether there is not intra-party transparency, because it is more effective than the voter’s punishment to prevent the corruption.