有尾噬菌体目(Caudovirales)，caudo由拉丁文的cauda而来，有尾状的意思。本目的病毒主要的宿主为细菌和古细菌，感染宿主时会利用尾状的结构，将DNA注入宿主中。在生物技术方面，有些种类的尾状噬菌体能作为病毒（例如：疱疹病毒科）的载体，用于基因复制和创建基因库的功能上。

The Caudovirales are an order of viruses also known as the tailed bacteriophages. Under the Baltimore classification scheme, the Caudovirales are group I viruses as they have double stranded DNA (dsDNA) genomes, which can be anywhere from 18,000 base pairs to 500,000 base pairs in length. The virus particles have a distinct shape; each virion has an icosohedral head that contains the viral genome, and is attached to a flexible tail by a connector protein. The order encompasses a wide range of viruses, many of which containing genes of similar nucleotide sequence and function. Some tailed bacteriophage genomes can vary quite significantly in nucleotide sequence, however, even among the same genus. Due to their characteristic structure and possession of potentially homologous genes, it is believed these bacteriophages possess a common origin.