Biomarkers can benefit many phases of the drug development process, ranging from drug discovery to preclinical development through each phase of clinical trials. Both the FDA and the industry have viewed successful integration of biomarkers into drug development as one way to help reduce the astronomical cost associated with bringing a new drug to the market. The aim of this roundtable is to share the experiences from both the FDA and the industry so far, with emphasis on biomarker validation and application to treatment selection. The discussion will be based on an initial brief review of some of the related guidelines and recommendations that have been published.