The advent of next-generation sequencing has demonstrated that eukaryotic genomes are extremely complex than what were previously thought. Recent studies revealed that in addition to protein-coding genes, nonprotein-coding genes have allocated a large fraction of the genome. Long noncoding RNA (lncRNA) genes are classified as nonprotein-coding genes, serving as a molecular signal, decoy, guide and scaffold. They were suggested to play important roles in chromatin states, epigenetic and posttranscriptional regulation of genes. Aberrant expression of lncRNAs and changes in their structure are associated with a wide spectrum of diseases ranging from different types of cancer and neurodegeneration to ?-thalassaemia. The purpose of this study was to summarize the current progress in understanding the genomic bases and origin of lncRNAs. Moreover, this study focusses on the diverse functions of lncRNAs in normal cells as well as various types of disease to illustrate the potential impacts of lncRNAs on diverse biological processes and their therapeutic significance.