This technical manual introduces the theory and practice of Quality Assurance/Quality Control (QA/QC) of seed quality in maize breeding and seed production. It focuses mainly on the genetic quality related issues of the improved maize seed. The seed quality program typically involves Quality Assurance (QA) which focuses on prevention of low-quality or genetically impure seed to be mixed with high-quality seed, while Quality Control (QC) in seed production chain ensures identification and correction of possible errors or mixtures that might have slipped through QA protocols. The manual outlines in detail the advantages of undertaking QA/QC in maize breeding and seed production by complementing the morphology-based testing (grow-out test) with the molecular markers-based analysis, especially in terms of testing for genetic purity and identity, parent-offspring test, and trait-specific testing using breeder-ready molecular markers. It also highlights the procedure for effectively monitoring the kernel-based nutritional quality traits (e.g., QPM and provitamin A) in maize breeding and seed production.