BPMS (Business Process Management System) represents a type of software that automates the organizational processes looking for efficiency. Since the knowledge of organizations lies in their processes, it seems probable that a BPMS can be used to manage the knowledge applied in these processes. Through the BPMS-KM Support Model, this study aims to determine the reliability and validity of a 65-item instrument to measure the utility and the use of a BPMS for knowledge management (KM). A questionnaire was sent to 242 BPMS users and to determine its validity, a factorial analysis was conducted. The results showed that the measuring instrument is trustworthy and valid. It represents implications for research, since it provides an instrument validated for research on the success of a BPMS for KM. There would also be practical implications, since managers can evaluate the use of BPMS, in addition to automating processes to manage knowledge.