This study evaluates the seismic performance of a six-story hospital building in Muscat, Oman using Incremental dynamic analysis. The building is a reinforced concrete flat-slab system with peripheral beams having a height of 25.2 m. The building has footprint of 65 m x 74 m that is divided into four portions through expansion joints with four shear walls. ETABS is used for the numerical modelling of the building considering all possible geometric details. The natural period of the building is estimated as 0.87 sec, which agrees with estimates suggested by the Omani Seismic Design Code. The nonlinear structural behavior is modeled using plastic hinges as per ASCE 41-13. Natural earthquake record matching the elastic response spectrum for the location is selected from the Pacific Earthquake Engineering Research Center (PEER) database. First-mode spectral acceleration is chosen as the intensity measure and the damage is measured using the maximum inter-story drift. 10 simulations are run using the record with varying scales until the collapse is observed for the Incremental dynamic analysis (IDA). Each simulation produced a single discrete Intensity vs Damage point. The building is assessed for Immediate Occupancy and Global Instability limit states. The immediate occupancy-damage control was identified as 0.084 g, which is well above the site-specific design spectral acceleration of 0.067. The results indicate that building satisfies drift limits and immediate occupancy criteria.