This book grapples with the exercise of self determination at the sub state level in Ethiopia''s Federation considering Oromia nationality administration as a case. The major objective of this study is to examine how the Oromos of Amhara regional state exercises their right to self determination and argued that the establishment of Oromia nationality administration manifested exercise of self determination as self administration to Oromos of Amhara region. However, this paper contends that external self determination for ONA seems unlikely due to the culmination of various factors. The study discussed the manifestations of self determination as the establishment of institutions of self governance: Oromia nationality council, administrative council and judicial bodies; cultural and linguistic rights; representation at the federal and regional level as well as socio economic opportunities self determination brought to ONA. Ethnic relation and political dynamics of the zone alongside future scenario and implications have also been analyzed.