The folded structure induced by theN‐aminoproline residue (the hydrazino analogue of proline, denoted hPro) in the Boc‐Gly1‐hPro2‐Gly3‐NHiPr hydrazino tripeptide has been characterized in the solid state by X‐ray diffraction, and compared to the usual βII‐turn structure in the Boc‐Gly1‐Pro2‐Gly36‐NHiPr cognate tripeptide. It is stabilized by a bifurcated hydrogen bond in which (Gly3)NH interacts with both (Gly1)CO and (hPro2)Nx. This conformation is retained in CH2Cl2and CHC13solutions, and allows an overall folded conformation of the hydrazino tripeptide in which (iPr)NH is hydrogen‐bonded to (Boc)CO. The hPro α‐hydrazino acid residue appears to promote a local folded structure, and might behave as a β