Metagenome-assembled genomes (MAGs) are reconstructed from sequence fragments recovered from a microbial community. They can provide genomic insight into organisms that are difficult to culture, but their completeness, contamination and ability to represent a single population all need careful consideration. This session introduces the benefits and challenges of using MAGs to study microbiomes.We will explore how MGnify generates MAGs and organises both MAGs and isolate genomes into publicly available biome-specific catalogues. Examples will show how to browse genome taxonomy and annotations, compare a user-provided genome with catalogue genomes, and how to use read-level evidence to guide follow-up checks and improvements for a genome. The session closes with the route for contributing reads, assemblies, bins or MAGs to ENA using nf-core/seqsubmit, and how to update genome catalogues with new members.This event is part of the webinar series “Making sense of metagenomics data with MGnify”. You can follow the link for more information about the series and its webinars.