<p>The question of when an individual ought to be able to plead the defence of duress in respect of serious violations of international criminal law has not been resolved by the decision to include a form of duress in the Rome Statute. The final definition is complex and contains many caveats, raising the question of whether it could ever be pleaded successfully. There is further complication created by the reference to duress in the Rules of Procedure and Evidence attached to the Statute, where it is used as an example of a mitigating circumstance, submitted to lessen the punishment imposed where there are ‘circumstances falling short of constituting grounds for exclusion of criminal responsibility.’ Recent jurisprudence demonstrates that the interpretation of duress as both a defence and a mitigating circumstance has not clarified the doctrine in international criminal law; the rules around duress as a mitigating circumstance are now connected to the threshold set for duress as a defence. This work argues that reform is required to address the lack of clarity around the definition of duress in mitigation, in a bid to resolve the difficulty of applying the rules in complex cases of responsibility.</p>