Standard hospital CPR policies in many countries require CPR to be attempted on all patients having a cardiac arrest unless a Not-for-CPR order is in place. It has recently been shown that this approach is legally inappropriate in New Zealand. It appears that this argument may also potentially apply in other common law countries given the role that 'best interests' has in these jurisdictions in providing treatment to patients lacking decision-making capacity. Not-for-CPR orders provide an important and transparent mechanism for making advanced decisions regarding resuscitation. However, advanced planning is not always possible and it is legally inappropriate to require CPR to be performed when it is not in the patient's best interests. Notwithstanding the difficult practical balance that exists at the time of arrest between initiating CPR without delay or interruption for it to be effective for those whom CPR is in their best interests, and recognising as quickly as possible those patients for who CPR is not appropriate, it is argued that policies should be modified to allow clinicians to consider whether CPR is appropriate at time of arrest. Such a change may require ALS training to include a stronger emphasis on early recognition of patients for whom CPR is not in their best interests.