Iterative development methodology has been widely adopted in recent years since it is flexible and capable of dealing with requirement volatility. However, how to quantitatively manage iterative projects, and in particular, how to quantitatively manage defects across multiple iterations, remains a challenging issue. There is lack of quantitative defect management support for iterative projects due to the difficulty in selecting appropriate control points and measures to collect and analyze data, and determining the “sweet spot” amount of effort for performing testing and defect fixing activities. In this paper, we first propose the BiDefect (process-performance Baselines based iteration Defect management) method to support quantitative defect management in iterative development. Then we report an industrial experience that a Chinese telecommunications company, ZZNode, successfully applied the BiDefect method in initial estimating, analyzing, re-estimating, and controlling defects for iterative development projects.