An overview, with 49 refs., of basic concepts and computer-based tools in org. synthesis design used to generate the synthesis tree and search for new multi-step synthetic pathways, reaction steps and conditions, to select the starting materials and to predict possible by-products. In particular, the methods based on biomimetic-type transformations (domino, tandem, multicomponent reactions) were recommended for selection of the shortest multi-step sequence (min. no. of reaction steps) starting from simple substrates in a one-pot procedure.