We have investigated the conformational preferences of a newly synthesized Cα,α symmetrically disubstituted glycine, namely α,α-dicyclopropylglycine (Dcp). We report here the crystal structure of a fully protected dipeptide containing Dcp, namely ZDcp1Dcp2OCH3. Both Dcp residues are in a folded conformation. The overall peptide structural organization corresponds to an α-pleated sheet conformation, similar to that observed in linear peptides made up of alternating D- and L-residues and in ZAibAibOCH3 (Aib: α,α-dimethylglycine). These preliminary data suggest that the Dcp could represent an alternative as molecular tool to stabilize folded conformations. © 2000 John Wiley & Sons, Inc. Biopoly 53: 182188, 2000