Stellate cells are principal producers of extracellular matrix proteins in the liver and play a major role in the development of liver fibrosis. Molecular basis of the cell activation has therefore been analyzed intensively during the past decade. Proteomics analysis is one of the most powerful tools with which to reveal the total protein synthesis in stellate cells, in particular the dynamic change in their expression level in response to activation. We have successfully analyzed over 300 stellate cell proteins by proteomics, several of which represented activation-associated change. Change in the level of some of these proteins was confirmed in liver tissue level. In addition, this approach led to the discovery of a novel globin in the vertebrate. Thus, proteomics is a research method for comprehensive understanding of the molecular basis of liver fibrosis.