This thesis aim at discussing the major problem of federalism in Nigeria under the Presidential Constitution which stems from the lack of proper understanding among the leaders of the principle behind the federal system, as manifested in the intense rivalry, confrontation, conflict of interest and difference of opinion between the Federal and State Government that characterised the Second Republic, The autonomy of each tier of government was misconstrued to mean competition and confrontation, with each trying to frustrate the other, whereas the conception underlying the system is that the federal and State Governments are mutually complementary parts of asingle governmental mechanism, federalism demands of them co-operation with one another in order to promote the welfare of the people through their combined efforts. To the common man living within the territory of a State, it is a matte* of little or not importance which of the two governments operating there has the constitut ional power to provide a particular service. Since the two must have between them the necessary power it is legitimate for him to expect them to co-operate in looking after his welfare. Conflicts between the two tiers of governments manifested in various areas, i.e . the non acceptance of the Presidential Liaison Officers by some State Governments, the use and control of the police, the controversy over the revenue allocation formula, the refusal of some State Governments to make land available to the federal Government for the building of the low cost housing units and the control of the mass media. But of all the confrontational stance of the State Government towards the Federal Government the most obvious was the demolition by the Oyo State Government of houses under construction at Ibadan by the Federal Government in order to solve the accomodation problem of the people of the State, • on the flimsy excuse that the land on which the houses were being built had not been granted to Federal Government, The use and control of the police was the source of much rancour and confrontation. There was the dispute about the constitutional propriety of the adaptations made by the President in the Public Order Act 1979- The revenue allocation formula enacted in 1981 generated a lot of controversy. The whole exercise was politicised. The non – NPN controlled States averred that the Federal Government manipulated the membership of the Joint Finance Committee appointed to resolve the difference between the formulae recommended by the House of Representatives and Senate, to suit their interest, and that was why they were denied the larger share recommended for them by the House of Representatives in the final report of the Finance Committee. The Federal Government was also involved in this unnecessary confrontation with some of the State Governments. The jamming of the television station of Lagos State by the Federal Government controlled NTA is an example of such confrontation. The multiparty system adopted by the country during the Second Republic was responsible for all conflicts and confrontations between the Federal and State Governments. The State Governments not controlled by the NPN refused to accept the leadership of the NPN Federal Government and felt that the only way they could score a political point was to frustrate the NBT Federal Government. This, it should be noted is disastrous for the political system of a developing State. Ways by which the confrontations and conflicts could be reduced considerably or eliminated completely have been discussed.