The cartel is considered the most harmful anti-competitive practice; therefore the competition authorities were concerned about the continuous improvement of the legislation governing this practice. In order to stimulate companies to withdraw from participating to a cartel in the European Union, the leniency policy has implemented. The present paper aims at achieving the hindsight of the years 2009-2013 regarding the evolution of cartel cases detected both at EU level and in Romania. The research methodology used is the study of literature, followed by the analysis of the legislation governing the European cartel and the analysis of all decisions issued between 2009-2013, both by the European Commission and by the Competition Council of Romania. The paper is structured in four parts. The first part presents the cartel from the theoretical and legislative point of view. The second and third parts of the paper include the analysis of cartel cases detected both at European and national level. The following aspects were taken into account when analysing the cartel cases: the date when the decision was issued by the competition authorities, the number of companies involved in the cartel, the opening date of the investigation, the method of opening the investigation, the field in which the cartel operated, the duration of the cartel as well as the amount of the fine. The final part of the paper highlights a number of conclusions. In the reviewed period 22 cartel cases were detected in the European Union and 23 cartel cases in Romania. The amount of the fines imposed at a European level is 251 times higher than the fines imposed by the Competition Council of Romania. In the European Union there were 11 long-term cartel cases, 10 medium-term cases and only one case lasted less than a year. In Romania there have been detected 4 long term cartel cases, 7 medium-term cases and 12 cases of short-term cases.