The corticotropin-releasing hormone (CRH) plays a critical role in stress-response regulation in vertebrates. The activity of CRH depends on CRH-binding protein (CRH-BP). CRH-BP is considered to play a chaperoning role in stress. Limited information mainly from the insects is available on the molecular structure and functions of invertebrate CRH and CRH-BP. We cloned and sequenced a CRH-BP gene from the intertidal copepod, Tigriopus japonicus which was expressed at all the stages of development. Molecular phylogenetic analysis showed that T. japonicus CRH-BP was closely related to CRH-BP of honeybee and other insects. The highest level of CRH-BP transcripts was expressed in adult males followed by nauplius stage 1. The expression of CRH-BP was upregulated when T. japonicus was subjected to temperature or salinity stress. This study demonstrates that CRH-BP in T. japonicus might play a role in stress-response. However, establishing such a role demands further studies on CRH-BP from other invertebrates and their expression under stress.