The existence of the induced helical smectic A (S*A) phase was proved by textural, optical and calorimetric studies and by small angle X-ray scattering using binary systems which consisted of achiral 4-n-hexyloxyphenyl 4-n-octyloxybenzoate (C ↔ Sc↔ N ↔ I) and chiralN-(4-n-nonylphenylbenzoyloxy)benzylidene-S-1-benzylethylamine (C ↔ SA↔ I). The induced S*Aand cholesteric (N*) phases appeared even at small concentrations of the chiral compound (≈ 1 mol per cent) together with increases in the S*C↔ S*Atransition temperatures, compared those for the Sc↔ N transitions, and decreases in the θctilt angle. Structural factors are discussed as possible causes of the formation of the induced S*Ablue phases I, II and III, and another polymorphic state in the systems studied.