The transition states of the aldol reaction and their analogues are reported here for the design of the haptens generating catalytic antibodies. The structural and the electrostatic properties were calculated by an ab initio molecular orbital method and were compared using a graphic software. Two transition states that lead to the corresponding stereo isomers of the aldol products were characterized. Also, the suitable transition state analogues were found. It is suggested that the stereo selectivity can be controlled using the catalytic antibodies elicited against the haptens designed here.