In this paper, the investigation of the optimum designs for two types of concrete can-tilever retaining walls was conductedutilizing the artificial bee colony algorithm. Sta-bility conditions like safety factors of sliding, overturningand bearing capacity and some geometric instancesdue to inherent of the wall were considered as the design constraints. The effect of the existence of the key in wall design on the objective func-tion was probed for changeableproperties of foundation and backfill soils. In optimi-zation analysis, the concrete of the wall, which directly affectsparameters such as carbon dioxide emission and the cost,was considered as the objective function and analyzes were performed according to different discrete design variables. The opti-mum concrete cantilever retaining wall designs satisfying constraints of stability conditions and geometric instanceswere obtained for different soil cases. Optimum designs of concrete cantilever retaining wall with the key were attained in some soil cases which were not foundthe feasible optimum solution of the concrete cantilever retaining wall. Results illustratethat the artificial bee colony algorithm was a favor-ablemetaheuristic optimization method togainoptimum designs of concrete canti-lever retaining wall.