Over recent decades experiments have been undertaken to reveal the optimum method for introducing earthworms into soils so the animals have greater chances of survival and are able to produce sustainable populations. This article describes development of the Earthworm Inoculation Unit (EIU) technique, its advantages over more traditional introduction methods and how it has been used. EIUs provide the means for sustainable earthworm population development even under harsh soil conditions, such as restored sites. However, certain circumstances dictate that this technique is not appropriate as digging in the soil/turf is unacceptable. Here more traditional methods can still be of value.