DNA sequencing is the discovery that uses the DNA composition to understand and decrypt the code of all biological life on earth as well as to understand and treat genetic diseases. Sequencing is the method of determining the order of nucleotides in a DNA molecule. It is determining the physical order of four bases thymine(T), cytosine(C), guanine(G) and adenine(A). As each organism’s DNA has unique sequence of nucleotides, determining the sequence helps in investigating the function of genes. The first sequencing technologies opened the door to study the genetic code of living beings. Most DNA sequencing has been performed using the chain termination method developed by sanger. This technique uses chain termination using modified nucleotide substrates. However, new sequencing technologies such as pyrosequencing and Illumina methods are gaining importance as these technologies give complete genome sequence information. Third generation sequencing methods are developed to overcome the limitations of second-generation sequencing methods like PCR amplification step which has the long procedure in execution time, expensive in sequencing and difficulty in genome assembly of relatively short reads. Now a days, these are the most commonly used sequencing platforms in the field of biotechnology.