Adherence or compliance to prescribed treatment regimens is an important and much debated area of haemophilia care. Many patients are labelled as 'non-adherent' because they don't do what we say in terms of self- treatment and factor administration. However, do we engage patients in developing mutually acceptable treatment programmes which work for them as individuals? If we do, does this affect self-care and treatment uptake through a supportive relationship which enhances treatment concordance? Once we have agreed treatment regimens, how do we measure the success or outcomes of them? This paper discusses these issues, and some of the tools that are available to assess adherence in a systematic way.