The use of antisense oligonucleotides as therapeutic agents has generated considerable enthusiasm in the research and medical community. Antisense oligonucleotides as therapeutic agents were proposed as far back as in the 1970s when the antisense strategy was initially developed. Nonetheless, it has taken almost a quarter of a century for this potential to be realized. The principle of antisense technology is the sequence-specific binding of an antisense oligonucleotide to target mRNA, resulting in the prevention of gene translation. The specificity of hybridization by Watson-Crick base pairing make antisense oligonucleotides attractive as tools for targeted validation and functionalization, and as therapeutics to selectively modulate the expression of genes involved in the pathogenesis of diseases. The last few years have seen a rapid increase in the number of antisense molecules progressing past Phase I, II and III clinical trials. This review outlines the basic concept of the antisense technology, its development and recent potential therapeutic applications.