AbstractThe current popular method in analysis and design phase is object-oriented analysis design (OOAD). The OOAD method aims to identify the objects which are responsible for their own. Mostly, the measurements of OOAD results are using verification and validation technique. A more demanding approach is expected from the OOAD method to improve software development process. To address this issue, this paper use Capability Maturity Model Integration (CMMI) as integrated software process improvement standard and approach. The purpose of CMMI is to improve process in creating product or services within organization. Therefore, the idea of improving process using CMMI will be applied for optimizing OOAD.The proposed method in this study is by constructing checklist criteria which already comply with requirement development process area in CMMI. Each criterion will be given certain score, then the score will summarize into total number from the assessment towards the Unified Modeling Languange (UML) Diagrams.The result obtained score of 185 for all criteria in the checklist and achieved 77,08% of CMMI level implementation, which categorized into Large Implementation (LI). The score also means that the UML diagrams are quite good and could be delivered through the next steps of software development life cycle.