Rebuilding programs for overexploited fish stocks are developed from identification of overfishing and depletion to the implementation of management measures to reduce fishing mortality and improve selectivity, to monitoring and adjustment of those measures based on performance. At each stage of a rebuilding program there are specific needs for scientific information and advice to guide management. Here we consider two case studies, North Sea cod and George's Bank groundfish and describe the development and implementation of their rebuilding programs and the information needs that enabled them. We conclude with a general framework for science advice for rebuilding plans.