Conformational analysis of two pairs of synthetic cyclodipeptides formed by interaction of both side chain functional groups ([InlineMediaObject not available: see fulltext.], and [InlineMediaObject not available: see fulltext.]) and of the main and side chains ([InlineMediaObject not available: see fulltext.], and [InlineMediaObject not available: see fulltext.]) was achieved by the method of molecular mechanics. The energetically optimal conformational states of the molecules under study were determined. It was shown that the conformational motility of cyclic system of the compounds under study depends on the relative arrangement of the amide groups and the number of atoms in the cycle. © 2008 MAIK Nauka.