In the context wherein multilevel governments persist, the institutions of intergovernmental relations(IGRs) are quintessential. In this light, this book examined institutions and practices of IGRs between Addis Ababa and Oromia,Ethiopia. The city of Addis Ababa and Oromia are inseparably related. The City is not only located within Oromia, but also interconnected in terms of socio-economic and political factors to the Region. This realities necessitate horizontal intergovernmental relations between Oromia and Addis Ababa.The book revealed that the party channel has a lion share in facilitating interactions between Oromia and Addis Ababa. Under the principle of dynamism, the current centralized party system via adopting all strategies and programs in the country has managed to play key role in the governance of the area. Nonetheless, the likelihood of having different partisanship at the different government levels in the area would challenge the significance of party network in the cooperation over contending matters. This book has both practical and scientific rationales for federal studies, intergovernmental relation studies, public administrations and others.