Abstract: An elevator car group control system for controlling a plurality of elevator cars arranged for parallel operation for serving a plurality of service floor landings of a building, comprising means for selecting suitable ones of the cars for serving hall calls, and means for forecasting the length of time required for each of the selected cars to arrive at each of the allotted hall call originating floors and displaying the forecast waiting time on display means disposed at the landing of each of the floors. In the invention, the serving car selecting means comprises means for detecting for each car the number of floors subject to change in forecast waiting time displayed at each of the already allotted floors when a new hall is originated from one of the floors, and means for preferentially selecting the car detected to provide a smaller number of floors subject to such change than the others.