Hi All, ISO is standard where any organisation can be certified. 9001:2008 for Infrastructure(if companies concentrates on infrastructure) 27001:Information security management system OHSAS etc. CMMI: Its a framework which gives best practices for improving process to quality and orgnisation objectives. CMMI have different categories CMMI for software development(CMMI development latest version is 1.3) CMMI for services(Latest version is CMMI services v1.2) CMMI for acquisition Normally CMMI services used in BPO and service oriented companies(in telecommunications also) SIX sigma: Its a philosophy,management system ,statistical approach. DMAIC and DMAIDV are most important concepts helps in engineering or reengineering the process. For CMMI ther certification process follows like below 1.SCAMP B and C appraisals by consultant(internal or external) 2.Finding the gaps and applying RACI matrix to complete actions 3.SCAMP A appraisal from SEI certified Lead appraiser 4.Finally certification signed by lead appraiser regards, -bala-