Polycyclic aromatic hydrocarbons (PAHs) and potentially toxic elements (PTEs) were monitored over 56 days in calcareous contaminated-soil amended with either or both biochar and Eisenia fetida. Biochar reduced total (449 to 306mgkg−1) and bioavailable (cyclodextrin extractable) (276 to 182mgkg−1) PAHs, PAH concentrations in E. fetida (up to 45%) but also earthworm weight. Earthworms increased PAH bioavailability by >40%. Combined treatment results were similar to the biochar-only treatment. Earthworms increased water soluble Co (3.4 to 29.2mgkg−1), Cu (60.0 to 120.1mgkg−1) and Ni (31.7 to 83.0mgkg−1) but not As, Cd, Pb or Zn; biochar reduced water soluble Cu (60 to 37mgkg−1). Combined treatment results were similar to the biochar-only treatment but gave a greater reduction in As and Cd mobility. Biochar has contaminated land remediation potential, but its long-term impact on contaminants and soil biota needs to be assessed. ► Biochar reduced total and bioavailable PAH concentrations. ► Biochar was less effective at immobilising PTEs, due to its low cation exchange capacity. ► E. fetida increased PAH bioavailability and PTE mobility. ► When used in combination biochar reduced the concentration of PTEs mobilised by E. fetida. ► Biochar had a negative effect on E. fetida in terms of weight loss. Biochar decreased PAH biovailability but was less effective at reducing PTE mobility, whilst E. fetida increased both PAH and PTE bioavailability.