Retinol-binding protein (RBP) is a transport protein that acts by solubilizing and protecting its labile ligands in aqueous spaces. It also has diverse and specific functions in regulating the disposition, metabolism and activities of retinoids (1). Retinol-binding protein is the specific plasma carrier of retinol, and encharged of the vitamin transport from the liver to target cells (2). Lower serum RBP level associates with diarrhea (3). High level of RBP in urine could be a good indicator of renal damage (4), microvascular complications with type-2 diabetes mellitus (5).