Monoclonal antibodies were selected after immunization with crystals of the tripeptide L-leucine-L-leucine-L-tyrosine. They interact with the tripeptide crystals, but do not interact with the tripeptide molecule, with other crystalline surfaces, or with adsorbed protein. The interactions of two antibodies with crystals of L-Leu-L-Leu-L-Tyr and of its enantiomer D-LeU-D-Leu-D-Tyr were characterized in depth. Antibody 48E is stereoselective and enantioselective: it recognizes only the {0(1) over bar 1} faces of the L-Leu-L-Leu-L-Tyr crystals, and not the enantiomorphous {01(1) over bar} faces of D-Leu-D-Leu-D-Tyr crystals, or any other faces of either crystal. In contrast antibody 602E is poorly stereoselectiwe and is not enantioselective: it recognizes the crystals of both enantiomers, interacting With a number of different faces of each. The different recognition patterns are explained on the basis of the nature of the interactions and the structure of the interacting surfaces. Understanding this antibody specificity advances our general understanding of surface recognition and transfer of chiral information across biological interfaces.