Quality assurance (QA) and quality control (QC) are the basic components of a QA program, which is a fundamental quality management tool. The quality of outputs and services strongly depends on the caliber of the communications between the 'customer' and the 'supplier.' A clear understanding of customer needs and expectations is essential to selecting and applying suitable QA and QC. Planning, implementation, and assessing all play a major part in the quality of final outputs. A clear understanding of the customer/supplier relationship and the functional roles played by each is essential to a successful QA program. The paper identifies, clarifies, and simplifies the quality management responsibilities of the customer and the supplier. The ideas presented are applicable in all work environments, including research and development (R&D).