Several individuals belonging to a new species of the genus Chromadorita (Nematoda: Adenophorea) were collected in a cold-seep area in the Gulf of Guinea during two French cruises: BIOZAIRE 2 (2001) and BIOZAIRE 3 (2003-2004) on board the R/V L'Atalante. In this area, rich chemosynthetic benthic communities have been discovered at 3150 m depth in the large pockmark field named Regab. Chromadorita regabi sp. nov. was found among the eggs in ovigerous specimens of the shrimp Alvinocaris muricola. The combination of long size (1500-2200 mu m), nine strong preanal papillae and relatively small dorsal tooth with weak musculature distinguishes this species from all known congeneric ones. An identification key to all known species of Chromadorita is provided.