Protein-protein interactions regulate almost all aspects of cellular signaling and aberrant protein-protein interactions have the potential to cause or contribute to human disease. The modulation of these interactions by drug-like molecules would offer previously unavailable opportunities to explore the relevance of pre-selected protein-protein interactions for cellular signaling, as well as benefits to patients. After an initial period of skepticism with regards to feasibility, there is now an encouraging set of data indicating that the effective and selective modulation of protein-protein interactions by drug-like molecules is attainable. This review highlights selected areas of current research that are aimed at identifying potent inhibitors of disease-relevant protein-protein interactions.