Abstract: Voltage stability problems in power systems are today, in many countries, one of the major concerns in power system planning and operation. This paper presents a preliminary analysis of voltage stability for Muscat power system. The modal analysis, Q-V curves and P-V curves methods are used in the analysis. The weak load areas in the system, which could lead to voltage instability, are identified using the modal analysis. The MVAr and MW margins (voltage stability margins) of the weakest load areas are determined using the Q-V and P-V curves. The modal analysis results show that South Batna load area is the weakest area in Muscat system, which could lead to voltage instability. The results also show that an increase in load demand on that area without an adequate increase of reactive power could lead the system to voltage collapse.