Dung decomposition in intensively grazed cattle pastures was investigated in four lowland and three upland plots and related to differences in dung beetle and earthworm abundance. Three experiments were performed to monitor dung decomposition in different seasons, starting in late spring, summer and autumn. In all the experiments decomposition was faster in the lowland plots which had higher temperatures and lower rainfall compared to the upland plots. In the spring and autumn experiments, between-plot differences in decomposition were closely related to differences in earthworm biomass. In the summer experiment earthworm abundance was low and between-plot differences in decomposition up to 40 days after deposition were correlated with differences in numbers of the larvae of Aphodius dung beetles. In the summer and autumn experiments, dung beetles were excluded from control pats by covering them with gauze tents for the first 20 days. This reduced decomposition over at least the first 40 days. In the summer experiment earthworm abundance was not significantly reduced in the control pats. In the autumn experiment earthworm abundance was reduced in the 20 day old control pats but not in the 40 or 60 day old samples. The gauze tents may have had an effect as a physical barrier to surface earthworm colonisation, while dung beetle activity may have increased earthworm aggregation in the experimental pats.