This paper aims at developing an understanding of optimal design solutions for three types of reinforced concrete retaining walls, namely, cantilever retaining walls, counterfort retaining walls and retaining walls with relieving platforms. Using genetic algorithms, parametric studies were carried out to establish heuristic rules for proportioning the wall dimensions corresponding to the minimum cost points. Optimal cost-estimates of the retaining walls types were compared to establish the best design alternative for a given height. Also, the advantages of retaining walls with relieving platforms, which are relatively new in India, are discussed.