Around 25% of the adult Type 1 diabetes population is in persistent poor glycaemic control and thus at increased risk of developing microvascular complications. We here discuss correlates of long-standing poor glycaemic control and review the efficacy of clinical strategies designed to overcome persistent poor control. Only a few studies have identified determinants and correlates of long-standing poor glycaemic control in Type 1 diabetes. There is some evidence implicating genetic factors, as well as lower economic status, and psychological factors, including lack of motivation, emotional distress, depression and eating disorders. Ways of improving glycaemic control include strategies to enable self-management, e.g. motivational strategies, coping-orientated education, psychosocial therapies, and/or intensifying insulin injection therapy plus continuous subcutaneous insulin infusion. Long-standing poor glycaemic control appears to be a heterogeneous and complex phenomenon, for which there is no simple, single solution. Comprehensive psycho-medical assessment in diabetes care may prove useful in tailoring interventions. Further research is warranted, to increase our understanding how psychosocial and biomedical factors, separately and in interaction, determine poor outcomes in Type 1 diabetes.