As a fundamental element of knowledge management (KM), knowledge identification is a crucial issue in contemporary business organisations. As evidenced by research, medium sized enterprises (MEs) contribute constructively and significantly to economic development, society stabilisation and employment increase. Their healthy survival and growth are of critical importance to a nation. Among the approaches ensuring the successful development of MEs, quality improvement (QI) is a crucial one. However, what is and how to identify the knowledge most relevant to the MEs' QI, the drives and sources for identifying the QI knowledge (QIK) as well as the underpinning rationales, are currently lacking of sufficient exploration. A research focusing on these issues has been strongly emphasised by literature and attested by this research itself of its meaningfulness. Through analysing empirical data collected and attested by a combination of firstly semi-structured interview, focus group following a case study strategy and then a structured interview, this exploratory research has obtained and prioritised the up-to-date answers to these questions, leading to the enrichment of the theoretical understanding of KM approaches in operations with a consideration of quality management. Real world MEs can rely on these findings as a guidance to obtain, select and apply appropriate QIK for their operations performance improvement. The findings can also be referential for knowledge identification and application in view of QI in other type business organisations.