Background and aims: We have previously demonstrated an association between increased abundance of Phascolarctobacterium and colorectal cancer (CRC) and adenomas in two independent Norwegian cohorts. Here we seek to verify our previous findings using new cohorts and methods. In addition, we characterize lifestyle and sex-specificity, the functional potential of the Phascolarctobacterium species and their interaction with other microbial species. Methods: We analyze Phascolarctobacterium with 16S rRNA sequencing, shotgun metagenome sequencing and species-specific qPCR, using 2350 samples from three Norwegian cohorts - CRCAhus, NORCCAP and CRCbiome - and a large publicly available dataset, Curatedmetagenomedata. Using metagenome assembled genomes from the CRCbiome study we explore genomic characteristics and functional potential of the Phascolarctobacterium pangenome. Results: Three species of Phascolarctobacterium associated with adenoma/CRC were consistently detected by qPCR and sequencing. Positive associations with adenomas/CRC were verified for P. succinatutens and negative associations were shown for P. faecium and adenoma in Curatedmetagenomedata. Men show higher prevalence of P. succinatutens across cohorts. Co-occurrence among Phascolarctobacterium species was low (