Cellular long-chain fatty acid (FA) transport and metabolism are believed to be regulated by membrane-associated and soluble proteins that bind and transport FAs. Several different classes of membrane proteins have been proposed as FA acceptors or transmembrane FA transporters. New evidence from in-vitro and whole-animal studies supports the existence of protein-mediated transmembrane transport of FAs, which is likely to coexist with passive diffusional uptake. The trafficking of FAs by intracellular fatty acid-binding proteins may involve their interaction with specific membrane or protein targets. Evidence is also emerging for concerted actions between the membrane and cytoplasmic fatty acid-binding proteins that allow for efficient regulation of FA transport and metabolism.