At light and electron microscopic level endocrine cells of the human embryos (9-31-week-old) appendices have been studied. They appear in the human embryo appendix on the 11th week of development for the first time. Amount of the endocrine cells in the field of vision increases significantly on the 17th-24th and does not change on the 25th-31st weeks. Basing on certain morphological criteria, presence of EC-cells and those resembling S- or I-cells is demonstrated in the human embryo appendix. Thus, already during the embryonal period there are cells in the appendix, main function of which is to produce biogenic amines and peptide hormones, participating in local regulation of homeostasis.