This paper presents the development of a new precast concrete floor system that eliminates the need for column corbels and beam ledges while being very shallow. The main criteria in the design of the proposed system include: span-to-depth ratio of at least 30, flat soffit floor system, resistance to lateral loads, economy, consistency with prevailing erection techniques, and fire and corrosion protection. The proposed system consists of continuous precast columns, partially continuous 254 mm. deep rectangular beams, partially continuous 254 mm. hollow-core planks, and a minimum of 51 mm. thick composite topping for six-story building with 9.75 m. X 9.75 m. bay size. The shallowness of the new system, its flat soffit, and resistance to lateral loads are the key advantages, which result in rapid, economic, and green construction. This paper presents the main concepts adopted in the system development as well as the design summary and construction sequence. The laboratory tests performed to ensure the structural performance of the proposed system are also presented.