Corruption has remained a thorn on the flesh of Nigeria’s economic, political and, social life in spite of the concerted efforts made to curb the menace by different regimes. In 2002, the Obasanjo’s Regime enacted the Economic and Financial Crimes Commission’s (EFCC) Act, while the Agency commenced duties with its plans of actions (policies) in 2003. Still, corruption was on the increase. The situation raised our concern to carry out a research work to examine Economic and Financial Crimes in Nigeria between 2003 to 2010. This research work has two questions which are: (a) Did EFCC’s activities (policies) strengthen the fight against corruption between 2003 to 2010? (b) Did EFCC effectively succeed in reducing corruption between 2003 to 2010? The two hypotheses tested in this research work are: (a) Political interference in the EFCC’s activities weakened the fight against corruption between 2003 to 2010, (b) Political interference in the EFCC’s policies undermined the EFCC’s effectiveness in reducing corruption between 2003 to 2010. We adopted structural functionalism as our theoretical framework and, used observational technique and qualitative descriptive method as our methods of data collection and analysis respectively. The first hypothesis was tested in chapter three, under the sub-heading, Obasanjo’s Regime (1999-2007), and we found out that such cases as the N81 billion Identity Card scam, the uninvestigated N250, 000 credited into the accounts of the members of the National Assembly, the EI-Rufai’s Privatization scandal, the Julius Makanjuola’s case, the many private establishments owned by Obasanjo etc, which were not investigated by the EFCC due to Presidential involvement, interference and, fear of indictment confirmed our hypothesis that political interference in the EFCC’s activities weakened the fight against corruption. The second hypothesis was tested in chapter four which has the headingEFCC’s Policies, Performances and Challenges. Under which we found out that the poor position of Nigeria in the Transparency International Corruption Perception Index, the use of the EFCC to destroy enemies and protect associates etc, confirmed our hypothesis that political interference in the EFCC’s policies undermined the EFCC’s effectiveness in reducing corruption. We concluded that EFCC was established to serve the interests of the ‘powers that be’. And that the use of the EFCC to protect the interests of the ‘powers that be’ weakened the EFCC’s activities and, undermined the EFCC’s effectiveness in reducing corruption in Nigeria between 2003 to 2010. We proffered recommendations that, there is need to strengthen the independences of the EFCC and, empower complementary governmental agencies and civil society organizations so as to engender the feelings of ownership of the war. If the government and the EFCC would accept and implement these recommendations, they would enhance the Agency’s (EFCC) effectiveness and efficiency.