Adipose tissue is specialized in the storage of energy in the form of triacylglycerol. Within the fat cell, triacylglycerols are found in a well-defined structural compartment called the lipid droplet, which occupies the vast majority of the fat cell volume. However, many other lipids are present in the lipid droplet. These include sterols, carotenoids, cholecalciferol and lipophilic toxic pollutants of the environment such as dioxins and tocopherols. The topic of this article is the role of fat cell cholesterol in adipose tissue physiology and its potential implication in pathological states such as obesity.