This report presents an ultrastructural study of normal subcutaneous fatty tissue. From well-know morphological facts on human adipocytes in adults we have been able to make the following additional observations: (a) Several lipid droplets were surrounded by a well-developed system of filaments; (b) material very similar (the same electron-density) to the central lipid droplet appeared within the smooth surfaced cisterns of the endoplasmatic reticulum; (c) complex lipid granules very probably corresponding to lipofuscin were present in the cytoplasm; (d) in the nuclei, often sphaeridia of the filamentous type appeared; (e) the quantity of so-called lipomicrons (electron-dense granules) is dependent on the method of fixation.