Introduction Nowadays, new methods have been developed to reduce the cost of diseaserelated laboratory methods and to achieve the shortest response time, which in a short time, determine a large portion of the genome. These methods are known as the next generation sequencing techniques. One of the most common application of such as these methods is diagnosis of disease. The aim of this study was to investigate the performance of Illumina next generation sequencing. Conclusion With the advanced technology of sequencing the whole genome, determining the structural changes of the genes, comprehensive studies of the number of genes, the identification of polymorphism, spot mutations and small mutations, the study of the expression of genes, and other applications are possible. In this method, first, the whole genome is broken into double strand DNA fragments; then, the bumps of fragmentation are converted to the smooth end, and adapters are connected to both ends of the components, and the sample pieces of the gene are connected to the flow cell with the help of hybridization by the same adapters. In the next step, centralized colonies of fragments (clusters) are formed through amplification of samples, using the bridge method, which subsequently, could be read. In a chemical reaction, the growth inhibitors will be taken by the end of 3’ and a new cycle begins. The mentioned step is continued until the sequence of whole cycle of the fragment is detected. The sequences of the whole genome are, then, determined with reference sequences, and ultimately the results are compared with the panel of genes associated with the disease and the changes are determined. Different methods can identify changes in the gene area and, in some cases, with investigating the rare changes, the relationship between these changes and the diagnosis of certain diseases can be known.