The isolation of Clostridium botulinum from the home environment of New South Wales patients with infant botulism is reported. Of the three cases of infant botulism type B, the bacteria were isolated from soil around the dwelling in one, and from tank rainwater in another. In one case with type A, the bacteria were present in the soil, vacuum-cleaner dust, and tank rainwater. The bacteria were not detected in the environment of two adult patients and a child with C. botulinum in their stools. The home location of the patients with infant botulism, and the frequency of isolation of the bacteria from rainwater, soil and vacuum-cleaner dust in Cobar, Nyngan, some Sydney suburbs, and at five pastoral homesteads suggest that infants in rural areas are more at risk than those in large metropolitan areas. The age of the infants with diagnosed botulism in New South Wales, compared with those reported in the United States data, strongly suggests that the disease is not being fully recognised in younger infants.