The European Food Safety Authority (EFSA) asked the Panel on Plant Protection Products and their Residues to provide guidance on methodology for performing probabilistic dietary exposure assessment of single or multiple active substances, as a potential additional tool to supplement or complement the standard deterministic methodologies which are currently used in the EU for conducting dietary exposure assessments for pesticides. Specific guidance is provided for basic assessments but not for refined assessments, where specialised expertise is required to select methods appropriate to the assessment in hand. The guidance includes probabilistic methods for quantifying some of the major sources of variability and uncertainty affecting dietary exposure to pesticides. Other important sources of variability and uncertainty might be quantified probabilistically in refined assessments but are addressed more simply in basic assessments by conducting alternative model runs with optimistic and pessimistic assumptions. Guidance is provided on problem formulation, including definition of appropriate scenarios for acute and chronic exposure assessment in the differing contexts of approval of new substances, MRL setting, authorisation of products, evaluation of residues found above the MRL, and annual reviews of residue monitoring data.