The chapter ‘Epidemics: a disaster of the nineteenth century’ analyzes the causes, the spread, the spatial pattern and the impact of the epidemics of syphilis in the A&N Islands in the late nineteenth century. It identifies how the tribal population was rendered vulnerable by the colonial actions which became the root cause for disaster in which nearly 98 per cent of the tribal Andamanese were exterminated. The British set up a penal colony in the A&N Islands in 1857 to colonize the A&N Islands. They met with stiff resistance by the tribal Andamanese, who retaliated by attacking the growing penal colony. To contain the attacks, the British set up an institution of ‘Andaman Home’, an asylum to keep tribal Andamanese and ‘civilize’ them which became the ‘breeding ground of epidemics’ because here Andamanese were exploited sexually by the convicts (also maybe the British) placed as guards of these Homes. The concentration of the deaths among the tribal Andamanese of the Homes proves that vulnerability of the tribal exposed to alien disease led to the epidemic.