The study of market analysis and assessment in medical service industry on regenerative medicine for knee treatment is a qualitative research with the objectives to analyze a market potential, to assess a possibility of knee treatment by regenerative medicine and to evaluate important factors for competing in regenerative medicine business in Thailand. A qualitative study based on in-depth interviews was employed. The informants are professionals who work in cell therapy medical centers or clinics and the patient service staffs or medical consultants who have direct contact with patients prior to making decision to receive treatment. The result showed that current trend signified tremendous rooms for growth in regenerative medicine business since most patients inclined to accept knee treatment by cell therapy. However, another important factor that could encourage (or impede) a growth of regenerative medicine business is the relevant law,rules and regulations issued by the Medical Council of Thailand.