Managing knowledge integrally as one of the company's asset is now a necessity to be part of the knowledge-based economy in the global industry. PT Cellular Tbk. (Cellular) has been a player of mobile communication service for more than 20 years. Cellular shows business transformation through increased gross revenue from Data services while declining revenues of voice and SMS services happening in most of the Operators. Cellular started implementing knowledge management (KM) in 2006, however, a new initiative was just launched back in 2015 to be in line with the business strategy today. This study discusses the sustainability of KM at Cellular with a review to the previous KM program and suggested an improvement to ensure that new KM initiatives will sustain. The study was conducted by analysing and assessing the level of maturity of KM in cellular with limitation to one of the business strategy regarding product innovation, technology planning and implementation of projects.