Using modern NMR techniques, including COSY, HOHAHA, 2D J spectrum. NOESY, HETCOR and HMBC, determination of C-13 T-1 spin-lattice relaxation times, and molecular modeling, permitted the full assignment of all H-1 and C-13 chemical shifts and geminal and vicinal coupling constants of cycloartenol. Stereochemical assignments related to the solution conformation of cycloartenol established unambiguously the nucleus assumes a flat structure and the side chain orients preferentially into a "right-handed" conformation, i.e.. 20 alpha-H atom is in front and opposing (in a 1,3-diaxial relationship with) the C-18 angular methyl group thereby positioning C-22 to the right of C-20 (H-20 trans oriented to H-17) in the usual view of the molecule. The crystal structures of two naturally occurring 9 beta, 19-cyclopropylcycloartenol metabolites, 3-normethylcycloartenol and 4,4-dinormethylcycloartenol, have also been determined and found to possess a three-dimensional shape similar to that of cycloartenol. The biosynthetic implications of these findings are discussed in relation to the cyclization of squalene oxide to cycloartenol.