This paper presents small-disturbance stability studies of the interconnected power systems of the Sultanate of Oman and the State of the United Arab Emirates. The two systems are interconnected through the existing 220 kV double circuit transmission line between Oman and Abu Dhabi leading to a rather longitudinal structure power system. The objective of the paper is to assess the inter-area oscillation damping of this interconnected system during small amplitude disturbances by using eigenvalue analysis. A detailed model of the interconnected system is obtained including representation of generators, prime movers, speed governors, exciters, automatic voltage regulators, transmission lines, transformers, compensators and loads. The system eigenvalues are calculated at various operating scenarios, including peak and minimum loading conditions with zero and maximum power exchanges in both directions and also during N and N-1 conditions. The results have shown that both systems have adequate damping before being interconnected. After interconnection, the eigenvalues profile indicates that the system will remain stable and satisfactorily damped for the considered power exchanges.