The mBreatheFreely handbook was prepared by an international group of experts in mHealth for asthma and COPD, in collaboration with WHO and ITU, to provide guidance for country governments and policymakers to develop, implement, and evaluate an mBreatheFreely programme for the prevention and control of asthma and COPD. The health messaging provided in the handbook uses evidence-based behaviour change techniques to help persons at risk of, with, or caring for those with asthma and COPD, prevent and manage these conditions. This handbook describes the considerations and decisions to be made in planning a national mBreatheFreely programme in five key areas: 1 Operations management 2 Content development and adaptation 3 Promotion and recruitment 4 Technology specifications 5 Monitoring and evaluation For each area, evidence-based operational guidance and resources are given, which can assist governments in drawing up a detailed workplan for a national mBreatheFreely programme. Subsequent annexes provide information on existing programmes, example programme algorithms and message content, timelines and costing templates