Only 20 years after the discovery of small non-coding, single-stranded 
ribonucleic acids, so-called microRNAs (miRNAs), as post-transcriptional gene 
regulators, the first miRNA-targeting drug Miravirsen for the treatment of 
hepatitis C has been successfully tested in clinical Phase II trials. Addressing 
miRNAs as drug targets may enable the cure, or at least the treatment of 
diseases, which presently seems impossible. However, due to miRNAs' chemical 
structure, generation of potential drug molecules with necessary pharmacokinetic 
properties is still challenging and requires a re-thinking of the drug discovery 
process. Therefore, this chapter highlights the potential of miRNAs as drug 
targets, discusses the challenges, and tries to give a complete overview of 
recent strategies in miRNA drug discovery.