Dementia is not the only long-term condition (or Chronic Disease) that develops as we age. There are many other long-term conditions that are on the increase within the wider population as a result of population ageing. People with dementia are not immune to these other conditions, in fact Barnett et al. (2012) indicate that seven in ten people who are living with dementia are also living with another concurrent medical condition and often more than one. This chapter looks at the commonest comorbidities that may arise and highlights the consequences of comorbidity and the impact and challenges that these cause to the person living with dementia and their carers. It considers what we can do to improve the way that health and social care professionals manage comorbidity, so that they can make life for the person living with dementia and their carers less stressful. However, the most significant thing that can be done is to reduce the occurrence of comorbidity amongst people living with dementia. This requires action to avoid the development of the chronic diseases responsible for most comorbidity earlier, by improving health promotion in midlife for everyone. For those who have a dementia with comorbidity now, the aim is to optimise care, deal with polypharmacy and create services adapted to best support carers in meeting the needs of those one who have both dementia and multiple long-term conditions. Unfortunately a great deal more work and further research is required to determine just what optimal care in the presence of a comorbidity looks like.