MicroRNAs (miRNAs) are small non-protein-coding transcripts that regulate gene expression posttranscriptionally by pairing with target messenger RNAs (mRNAs). It is predicted that humans express thousands of miRNAs and, although only a few hundred have been identified, there is already mounting evidence suggesting that they play an important role in several different developmental processes. It is therefore not surprising that miRNAs have been found to be deregulated in many diseases. The discovery of miRNAs has uncovered a natural form of controlling RNA transcription and translation, which could provide new avenues for diagnosis, prognostic, and therapeutic applications. This review summarizes some of the key recently published patents and relevant research advances on miRNA target identification, strategies to modulate their activity and the potential applications in human diseases such as cancer and viral infections, as well as methods and techniques for purification, detection and quantification of miRNAs.