The importance of managing quality in developing software systems is well documented. Existing literature presents attributes of good quality management practices in building software systems on time, within budget, and satisfying customer needs. However, most of the current findings on Software Quality Management (SQM) are case-based and company-specific, and may not be generalizable across all software developing organizations. Furthermore, the relationships examined in past research may be incomplete and therefore fail to identify differing dimensions critical for SQM. Against this backdrop, our research provides a synthesis of existing literature by identifying six critical factors of SQM in software developing organizations. An instrument that can be used to measure critical factors of SQM is constructed. Validity and reliability of the instrument is established using a combination of exhaustive literature review, pre-pilot testing a preliminary version of the instrument among a group of academics, and pilot testing revised versions of the instrument among a group of IS professionals who are affected by software quality. An instrument such as the one proposed in this research could be used by senior IS managers to assess the effectiveness of SQM practices in developing quality software. Researchers on the other hand could use the instrument to better understand SQM practices, and build theories and models to manage software quality effectively.