<p>Background: Particpants (n=72) were recruited from four service user support groups in the United Kingdom to take part in a prospective, longitudinal study on exercises undertaken as part of a self-care programme. Aims: To investigate participants’ knowledge and beliefs about a lymphoedema exercise programme and examine the impact of an intervention involving the formation of implementations intentions on exercise adherence. Methods: A 3×2 mixed design related to time (baseline, oneand two-month follow-up) and implementation intentions. A 24-item questionnaire elicited information utilising constructs based on the theory of planned behaviour. Results: The two strongest predictors of participants’ intentions to adhere to lymphoedema exercise recommendations were anticipated regret (ß=0.32, p<0.01) and perceived behavioural control (ß=0.26, p<0.01). Analysis of both the within- and between participant effects suggested that the intervention was successful in increasing exercise adherence. Conclusions: Participants’ anticipated emotional response and perceived control regarding lymphoedema exercise are important factors to target in order to influence adherence. Encouraging the formation of specific plans around where and when lymphoedema exercises are undertaken may also promote therapeutic activity. Declaration of interest: None.</p>