A field experiment and two soil faunal surveys were carried out to determine the effect of liming on earthworm populations of European forests. In the UK, a mixed species assemblage of earthworms was introduced into a deep peat soil under a young stand of Picea sitchensis, following addition of lime. Dendrodrilus rubidus was the only introduced species to be recovered after nearly a year. Total earthworm numbers and biomass were 70% and 15% of those introduced; this included species which had not been inoculated. Earthworms were found only where the soil had been limed; most individuals were found where earthworms and lime had been applied. In a survey of long-established limed plots of Picea abies on an acid, brown earth soil in northern France, liming increased earthworm density (5 to 11 individuals m−2, compared with 6 m−2 in a nearby deciduous woodland, and 0 m−2 in unlimed P. abies plots). Similarly, in Northern Ireland, the addition of lime permitted a substantial community of earthworms to develop in deep peat soil under P. sitchensis (79 individuals m−2, compared with 5 m−2 in unlimed soils), including acid intolerant species rare in coniferous soils. Different species assemblages were found in the four different limed plots sampled. The trees growing on limed soil at this site showed greater height growth than the trees in the unlimed plots, and it is suggested that earthworms have a beneficial effect in limed coniferous soils by increasing nutrient turnover.