The toxicity of sublethal polycyclic aromatic hydrocarbons (PAHs) levels in soils was assessed by testing their impact on expression of annetocin, a reproduction regulating gene, and translationally controlled tumor protein (TCTP), a tumorigenic response gene, in the earthworm Eisenia fetida cultured in artificial soil spiked with, phenanthrene (Phe), pyrene (Pyr), fluoranthene (Flu), or benzo(a)pyrene (Bap). Annetocin and TCTP were both up-regulated by 0.1 and 1.0 mg kg(-1) benzo(a)pyrene and TCTP was down-regulated by 10.0 mg kg(-1) phenanthrene. Weight loss and cocoon production of the worms were also analyzed. Only 10.0 mg kg(-1) phenanthrene impacted earthworm weight loss significantly and no significant differences on cocoon production were observed. Our study indicated that the potential ecotoxicity of sublethal PAHs in soil should not be neglected and mRNA transcription level in earthworms was a more sensitive indicator of PAHs exposure than traditional indexes using cocoon production as endpoints and/or using the whole-organism as the test materials.