Abstract: The principle of antisense technologies is based on the specific inhibition of unwanted gene expression by blocking mRNA activity. It has long appeared to be an ideal strategy to leverage new genomic knowledge for drug discovery and development. During the past 20 years the technology associated with the development of antisense has improved dramatically and emerging chemistries have made antisense oligonucleotides into powerful and versatile tools to study the function of proteins in living cells. In recent years, antisense technologies have been widely used as potent and promising tools for this purpose. There is a rapid increase in the number of antisense molecules progressing in clinical trials. Antisense technologies provide a simple and efficient approach for drug discovery and development and are expected to become a reality in the near future.