By reaction of 4-tert-butylphenoxyacetylhydrazide with aromatic aldehydes and acetone a new series of 4-tert-butylphenoxyacetylhydrazones was synthesized. The structural peculiarities of the investigated molecules have been determined by means of X-ray analysis and IR spectroscopy. The diagnostically important IR spectral criteria required for the conformational analysis of acethylhydrazones have been considered. It was established that the 4-tert-butylphenoxyacetylhydrazide in condensed phase exists only as a ZN-C(O)-conformer. Its derivatives exist as EN-C(O) and ZN-C(O)-forms. As a rule, the prevalence of ZN-C(O)-form has been observed in CCl4 solutions. The structure of investigated compounds is also determined by a system of inter- and intramolecular hydrogen bonds. The energy of hydrogen bonds was estimated.