CrAss-like phage are a bacteriophage (virus that infects bacteria) family that was discovered in 2014 by cross assembling reads in human fecal metagenomes. In silico comparative genomics and taxonomic analysis have found that crAss-like phages represent a highly abundant and diverse family of viruses. CrAss-like phage were predicted to infect bacteria of the Bacteroidota phylum and the prediction was later confirmed when the first crAss-like phage (crAss001) was isolated on a Bacteroidota host (B. intestinalis) in 2018. The presence of crAss-like phage in the human gut microbiota is not yet associated with any health condition.