Product quality is essential to ensuring pharmaceutical performance. Early quality issues and expectations for investigational drugs will be discussed. Quality by Design (QbD) is an initiative to improve pharmaceutical manufacturing being applied to small molecule development. Although the principles of QbD are applicable to biopharmaceuticals, there may be some unique considerations for these products. Advances in analytical strategies are an important part of QbD implementation for complex products and some examples of protein characterization that relate to clinical performance will be described. Potential approaches to link product attributes to safety and efficacy will also be discussed.