Liver fibrosis involves different cell types, and should be regarded as a "wound healing" response that occurres in conditions of chronic liver injury and is characterized by inflammation, activation of matrix-producing cells, matrix deposition and remodeling, and epithelial cell regeneration or an attempt thereof. Liver damage may be caused by several agents or conditions, resulting in different degrees and types of tissue inflammation and in activation of matrix-producing cells, such as the hepatic stellate cells (HSC). HSC undergo a phenotypic transition (known as "activation") to myofibroblast-like cells that synthesize different extracellular matrix components. Obesity is associated with the development of NASH, and has been indicated as an independent factor for the progression to fibrosis. In liver diseases, the biologic actions of the adipokines, such as leptin, adiponectin and resistin, released by adipocytes or locally produced by liver and/or inflammatory cells, may contribute to clarify the mechanisms of progression in NASH. The clinical and experimental findings accumulating on this class of molecules could represent the basis to devise a better management strategy for the patients with chronic liver disease.