Nitrogen-fixation symbiosis between non-legume plants and Frankia strains is the predominant N2- fixing system in forests. Actinomycete Frankia is of fundamental and ecological importance for its ability to fix nitrogen and to nodulate about 25 genera of plants. Here is a review on genomes of Frankia, including the organization, function, localization and some particular properties of its genes. Also a comparative analysis of Frankia nif genes from various strains and species was carried out. Novel trends in research on Frankia genetics were given in the end.