This chapter firstly describes target behaviours for chronic diseases, chosen based on their prevalence and potential for self-management: type 2 diabetes, chronic obstructive pulmonary disease, hypertension, heart failure, obesity, asthma and ischaemic heart disease. High-level target behaviours (e.g. diet, physical activity, medication adherence, smoking cessation, symptom monitoring and management) are presented for each of these diseases when applicable, accompanied by low-level target behaviours. Next, we address ways of assessing these target behaviours – diet, physical activity, medication adherence and smoking cessation – a necessary first step for understanding these behaviours and identifying needs.