Quality by design (QbD) has been receiving a lot of attention in the pharmaceutical community of late. Successful QbD implementation requires a thorough understanding of the relationship between the critical quality attributes (CQAs) and the clinical properties of the product, the relationship between the process and CQAs and the variability in raw materials. This article presents a roadmap for successful QbD implementation for therapeutic biotechnology products. The approach presented here is aligned with existing regulatory guidance documents. Key developments are reviewed and case studies are used to illustrate these concepts. It is concluded that although several QbD concepts are being practiced by the biotechnology industry, successful dialogue and partnership between the industry and its regulators will be the key to successful QbD implementation.