With the unprecedented growth of chemical databases incorporating up to several hundred billions of synthetically feasible chemicals, modelers are not in shortage of chemicals to process. Importantly, such "Big Chemical Data" offers humongous opportunities for discovering novel bioactive molecules. However, the current generation of cheminformatics software tools is not capable of handling, characterizing, and processing such extremely large chemical libraries. In this presentation, we will discuss the rationale and the main challenges (theoretical and technical) for screening very large repositories of compounds in the current context of drug discovery. We will present several proof-of-concept studies regarding the screening of extremely large libraries (1+ billion compounds) using our novel GPU-accelerated cheminformatics platform to identify molecules with defined bioactivity. Overall, we will show that GPU computing represents an effective and inexpensive architecture to develop, employ, and validate a new generation of cheminformatics methods and tools ready to process billions of compounds.