Lipid droplets are found in most cells, where they are needed for lipid metabolism and energy homeostasis. Their biogenesis is still not entirely described process, in which an organelle with monomolecular layer on the surface originates from two-layer membrane of the smooth endoplasmic reticulum. Large lipid droplets can be formed either by growth or by fusion of smaller lipid droplets. Their basic functions are controlled lipid deposition and lipid metabolism and the protection of the intracellular environment from lipotoxicity. Currently, dysfunction of lipid droplet is associated with a number of diseases such as obesity, cardiometabolic syndrome, tumor and neurodegenerative diseases, lipodystrophy and cachexia. Keywords: lipid droplet, adipocyte, endoplasmic reticulum, perilipin, obesity, type 2 diabetes mellitus, lipodystroph.