Mo toxicity to earthworms (Eisenia andrei), Collembola (Folsomia candida) and enchytraeids (Enchytraeus crypticus) was determined in 10 European soils and a standard artificial soil, freshly spiked with Na 2 MoO 4 , after 28 days exposure. Mo affected survival only in three low pH sandy soils; in all other soils LC50 was >3200mgMo/kg dry soil. EC50 values for the reproduction toxicity of Mo were 129–2378mg/kg for earthworms, 72–>3396mg/kg for Collembola, and 301–>2820mg/kg for enchytraeids. Variation in toxicity among soils could not be explained by differences in available (pore water, water and 0.01M CaCl 2 extractable) Mo concentrations. Clay content best predicted the EC50 for Mo toxicity to earthworms, while toxicity of Mo for enchytraeids was best described by soil pH. For Collembola no relationships could be derived due to the absence of toxicity in most soils. Soil properties had a strong but species-specific effect on Mo toxicity to soil invertebrates.