The theme of this study focuses on exploring the causes of conflict and viability of peace between Amhara-Tigray Regional States over Tegedie and Tsegedie Woreda borders. In the pre-1991 regimes, Tegedie and Tsegedie Woreda were peaceful. However, their post 1991 relationship is manifested either peaceful or conflictual. Their peaceful relation is manifested through their economic interdependence, as well as, shared socio cultural practices. The central objective of this study was to explore the causes, actors, and conflict management mechanisms, impacts of conflict and viability of peace over the 2017 peace agreement/border demarcation between Amhara-Tigray ethnic groups over Tegedie and Tsegedie Woreda conflicts. The study was undertaken to explore the nature of Tegedie and Tsegedie Woreda relations after the restructuring of the country along ethnic lines. Methodologically, the researcher employed qualitative research approach with case study research design. The researcher highly relied on primary sources of data; however, secondary sources of data were also used for triangulation purpose. The tools used to collect data were in-depth interview, telephone interview, observation and document analysis. Purposive sampling, a type of non-probability sampling was also used to select the participants for in-depth and telephone interview. The analysis of qualitative data was made in thematic Analysis. As per the finding of this study, in the study areas, conflicts mainly caused by; political, economic, social and security factors, good governance problems, boundary and weakening of traditional mechanisms of conflict resolution. The actors involved in the conflict were direct and indirect actors. Moreover, the study revealed the impacts of the conflict as; economic, social and political. To manage the conflict and build peace, formal and customary mechanisms of conflict management and peace building were undertaken. However, the attempts failed to address the root causes of the conflict and build lasting peace. Thus, as the finding of this study indicated, there is no guaranty for sustainability of the peace since the root cause of the conflict is not resolved.