This paper aims to assess seismic performance and cost efficiency of a 42-story reinforced concrete dual-system building, i.e. a centrally located core wall building with perimeter special moment-resisting frames, hypothetically located in Los Angeles, California. The building was designed based on two different design approaches by a renowned structural engineering company: (a) following the prescriptive design requirements of the International Building Code (IBC 2006) and (b) following performance-based design guidelines described in Los Angeles Tall Building Structural Design Council (LATBSDC 2008). Detailed analytical models were developed for each building design to assess seismic performance of the buildings at different hazard levels in terms of various response quantities. Comparisons revealed that a performance-based designed building experienced modestly less damage associated with smaller interstory drifts and lower core wall stresses, even though the difference between two designs was modest and excellent performance was observed in both buildings. From a financial point of view, the performance-based designed building required higher initial costs due to larger member sizes, yet, lower annual repair costs due to smaller amount of damage/loss. Copyright (C) 2015 John Wiley & Sons, Ltd.