Spiroconnected N-alkoxyalkylpiperidine hydantoins were obtained via the Strecker reaction of cyanohydrin with ammonium carbonate. 1,3,8-Triazaspiro[4.5]decane-2,4-diones have shown the myelostimulating activity in the artificially induced (with cyclophosphamide) myelodepressive syndrome. The compounds significantly accelerated the regeneration of lymphocyte and granulocyte cell pool of bone marrow hematopoiesis.