Owing to the complexity and variability of metagenomic studies, modern machine learning approaches have seen increased usage to answer a variety of question encompassing the full range of metagenomic NGS data analysis. We review here the contribution of machine learning techniques for the eld of metagenomics, by presenting known successful approaches in a uni ed framework. This review focuses on ve important metagenomic problems: OTU-clustering, binning, taxonomic pro ing and assignment, comparative metagenomics and gene prediction. For each of these problems, we identify the most prominent methods, summarize the machine learning approaches used and put them into perspective of similar methods. We conclude our review looking further ahead at the challenge posed by the analysis of interactions within microbial communities and di erent environments, in a eld one could call "integrative metagenomics".