AbstractElectron diffraction patterns obtained from single crystals of amylose complexed with n‐butanol are reported. The crystals were examined in the frozen state, after quench‐freezing in liquid nitrogen in order to maintain the complexed state in the electron microscope. The patterns may be indexed in the base plane with an orthorhombic unit cell of dimensions a = 27.0 ± 0.2 Å and b = 26.4 ± 0.2 Å, and the symmetry of the patterns is consistent with the P212121 space group. The relationship between the orthorhombic patterns and the pseudohexagonal patterns obtained by previous workers from dried crystals is discussed.