Metagenomics is the study of genomic content of samples from same habitat, which is designed to determine the role and the extent of species diversity. Targeted or random sequencing are widely used with comparisons against sequence databases. Recent developments in sequencing technology increased the number of metagenomics samples. MEGAN is an easy to use tool for analysing such metagenomics data. First version of MEGAN was released in 2007    and the most recent version is MEGAN6. First version is capable of analysing taxonomic content of a single dataset while the latest version can analyse multiple datasets including new features (query different databases, new algorithm etc.).