A review.Biopharmaceuticals, mainly protein-based therapeutics, are rapidly being developed for several disease indications.However, most biopharmaceuticals are 'me-too' drugs or are being developed against the same handful of targets.Thus, the potential of biopharmaceuticals is not being fully exploited.The bottleneck is still the lack of validated targets and the means of implementing the appropriate target validation technol.Functional proteomic screens provide a rapid route to accelerate the discovery and development of the next generation of biopharmaceuticals.