The national collection of parasitic nematodes, established in the 19th century, has developed since 1960 and its present diversity makes it one of the top three collections in the world. For parasites of vertebrates, it covers all groups of Secernentea (clades III, IV, V): Rhadiasides, Cosmocercides, Ascarides, Oxyurida, Spirurides, Trichostrongles, Metastrongles etc., while Adenophorea groups (clade I), are well represented (Trichinelloidea) or rare (Muspiceoidea) in the collection. For the arthopod parasites, Oxyurida and Rhigonematides make up the bulk of the collection. The Tylenchida and Mermithida are less well represented, as are the parasites of oligochaetes and molluscs. Specimens originate from around the world but tropical regions are particularly well represented. They were collected during MNHN missions or were gifts of French and foreign colleagues. In total the collection includes about 1000 lots of types, 2000 slides and over 25 000 lots in vials (a lot, preserved in 70% alcohol, corresponds to the sample taken from a host specimen and thus includes one to hundreds specimens, fixed in hot alcohol, or more rarely in 5-10% formalin).