This chapter provides an overview of the health threats and the likely public health challenges after natural disasters in the twenty-first century. Disasters not only lead to increased population risk and exposure to injury, communicable diseases and non-communicable conditions, but they also pose other threats to the population. Mental health consequences of disasters are influenced by psychological and social factors before, during and after the disastrous event. Infectious disease control is one of the common health strategies public health workers apply to protect population health. Sexual and reproductive health is a human right and presents significant public health challenges to be addressed in both emergency and non-emergency settings. Attention should also be paid to the mental and social health needs of patients, their families and frontline relief workers and the provision of rehabilitation or palliative care in accordance with the pathway of care approach to protect health.