The configurational analysis of racemic and optically active stereoisomers of 4-[(1’-methyl propyl)oxycarbonyl]-2-oxetanone has been carried out by using chiral gas chromatography. This technique has been successful in the stereoisomers composition determination of these p-substituted p-lactones prepared by two different routes and used as monomers in the preparation of malic acid stereocopolymers. Results are in good agreement with those obtained from high resolution H-1 NMR, in the presence of an Europium salt, as chiral shift reagent. This method has been extended to 3-methyl-4-[(1’,2’,2’-trimethyl propyl)oxycarbonyl]-2-oxetanone. The exact knowledge of precursors configurational structure is very important in regard to the obtention of the corresponding polystereoisomers with a strictly controlled enantiomeric or diastereoisomeric composition and consequently with predictable properties.