The thesis looks in to criminal laws and death penalty powers of the regional states in Ethiopia; the casernof Oromia and SNNPR State. Principally, the FDRE Constitution has established ethnic based selfgoverning federal arrangement and incorporates division of Legislative, executive and judicial powersrnwith dual Government structure. This federal arrangement has one major goal, providing the variousrnethno-national groups - 'Nations, Nationalities and Peoples' - of Ethiopia with the power to governrnthemselves through self rule and shared rule. Although the constitutional principles and the federalrnarrangement exemplify such features, the criminal laws power is centralize. Based on this, the main issuernaddressed in this paper is as whether the regional states are exercising criminal laws legislative,rnadjudicative and implementation power in general and death penalty in particular. To test this, thernwriter used descriptive and analytical qualitative technique. Primary data were collected from keyrninformants through interview. Countries constitutions, legal documents and other relevant documentsrnwere also used as secondary data. The writer after making serious analysis has reached the Followingrnfindings: In the federal arrangement substantive criminal law legislative power is vested with both thernfederal and Regional States. The regional states power is limited only to matters not specifically coveredrnby federal criminal code or laws. Criminal procedural law legislative power is reserved as residualrnpower for the regional states, however the Federal legislative organ exhaustively define all criminalrnmatters leaving almost no rooms for the regional states and take away the Regional states power andrnenacted centralized criminal code and laws. Following centralized federal criminal code, normativelyrnspeaking criminal laws adjudication and implementation power is also centralized. It is only the federalrncourt and federal criminal law enforcing agencies establishment proclamations that sufficiently definerntheir criminal jurisdiction while the regional states courts and criminal enforcing agencies have nornsufficient laws which determine their criminal jurisdiction. However practically criminal lawsrnadjudication and implementation is decentralized, as a result Oromia and SNNPR state courts assumernresidual criminal jurisdiction. With respect to death penalty implementation the issue is treatedrndifferently, although regional states are adjudicating capital crimes, the implementation of death penaltyrnrequires the blessing of the central government. It cannot be executed, pardoned or commuted unless thernhead of the state sign it. Based on the findings, the writer come up with the conclusion that for the realrnimplementation of federalism in criminal justice system, the Federal criminal code should be amendedrnand regional states should exercise their power to determine their own matters by themselves and as suchrndetermine state nature crimes and corresponding penalties to adjudicate and implement by themselves.