Megascolecidae is a large family of earthworms which has native representatives in Australia, New Zealand, Southeast and East Asia, South Africa and both South and North America. Primitive members of the family show a Gondwanan distribution and have been used as evidence of continental drift. Members of the Pheretima group of genera (e.g. Amynthas ) are widely distributed around the tropics, much as some Lumbricidae are distributed through the temperate zones. The North American native genera Diplocardia , Argilophilus, Driloleirus , Arctiostrotus and others belong to this family.

Many genera in the megascolecidae exhibit meronephry , where the nephridia , instead of being the primitive two per segment, have become broken up into many. Some taxa also exhibit enteronephry where the nephridia, instead of emptying to the body surface, empty into the gut.