This article is the result of a complete study of the functions of the Colombian National Police in the history and currently; in addition to a thorough study of the Colombian context to the peace talks for ending the conflict, carried out between the national government and the FARC, which have resulted in the Final Peace Agreement. start from these studies with the purpose to determine the effects it generates on citizen security the post-conflict and from there, determine the importance of the work of the National Police in preserving the life of society, the security of Colombians and maintenance the public order, in the interests of the preservation of peace. In this regard, it has been found that it is essential the National Police in the post-conflict as a guarantor of public security institution, in this scenario their functions remain focused on the welfare of citizens, but it needs strengthening to ensure compliance of their duties efficiently, since the challenges it brings the end of the conflict are big.