This document provides guidance on implementing a quality system approach to ensure compliance with cGMP regulations in a harmonized manner consistent with modern pharmaceutical practices. It outlines key concepts of a quality system, including design quality into products, risk-based quality management, change control, periodic quality reviews, supplier qualification, calibration, validation, complaint handling and recalls. The document refers to FDA's six systems inspection model and outlines four major factors of a quality systems model: management responsibilities, resource management, process management and quality planning. The goal is to help manufacturers understand and implement modern science-based quality systems and risk management.