A broader understanding of Federal system calls for thernstudy of the compartment on which the state to staternrelationship is based. In the context wherein multilevelrngovernments persist; studying the way how horizontalrnIntergovernmental Relations (IGRs) function are essential.rnBoth vertical and horizontal federalism are fundamentalrnelements of federal state structured government. Yet mostrnscholarship about federalism focuses on vertical, federalstate interactions while neglecting horizontal state-staterninteractions. In this light, this research examinedrninstitutions and practices of IGRs between Amhara andrnBenishangul Gumuz Regional States of Ethiopia. The twornRegional States are closely related in many respects. Thisrnreality necessitates horizontal intergovernmentalrnrelations between Amhara and Benishangul Gumuz RegionalrnStates.