Abstract: The present invention relates to an efficient and improved process for purifying a recombinant protein. The invention relates to the purification of tissue plasminogen activator (tPA), such as truncated human tPA, recombinantly produced in bacteria, for example in E. coli. The present invention provides a process that requires less refolding volume after solubilization of inclusion bodies isolated from cells expressing the recombinant tPA, without affecting the yield and purity of the tPA protein. The invention also provides optimum arginine concentrations for use during protein refolding and during ion exchange chromatography.