Through Dec 31, 1985, there have been six cases of infant botulism reported in Colorado. Three of these infants have lived in the same town of 800 people in western Colorado. Two of these three infants developed infant botulism within a six-month period in late 1981. The infants lived approximately 400 m apart; they had used the same crib at the time each developed botulism. A specimen from the crib yielded Clostridium botulinum, as did four soil samples from the town and house-dust samples from the home of a relative of the second infant. The third infant developed infant botulism in September 1984. This infant had not shared the crib. In this case, all seven samples of soil from various locations in the town yielded C botulinum, as did a sample of house dust from the home of this infant. The occurrence of these three cases in such a small town seems unlikely to be only coincidental. Investigations and reports of other such clusters may provide insight into modes of transmission of infant botulism.