High density lipoproteins (HDL) are heterogeneous particles regarding their size and composition. They have vital functions in reverse cholesterol transport (RCT). RCT occurs when lipid-free apolipoprotein AI recruits cholesterol and phospholipid to form nascent HDL particles. Adenosine triphosphate‑binding cassette transporters and scavenger receptor class B type I were found to be associated with the synthesis of HDL. Experimental studies have identified several potential anti‑atherogenic effects of HDL, including promotion of macrophage cholesterol outflow as well as anti‑inflammatory and anti‑thrombotic effects. HDL can also transport microRNAs. This review mainly summarizes the present knowledge of HDL synthesis and metabolism.