The recent development and evaluation of procedures for examination of fecal specimens for botulinal toxin and Clostridium botulinum have provided the means by which infant botulism can be recognized. The toxicity for mice of fecal extracts containing botulinal toxin can be neutralized with specific botulinal antitoxin. The presence of C. botulinum in the feces is detected by demonstrating the presence of botulinal toxin in enrichment culture supernatant by means of toxicity tests in mice. C. botulinum is isolated by streaking enrichment cultures on egg yolk agar and picking typical lipase-positive colonies. The experience of both the Center for Disease Control (CDC) Botulism Laboratory and other laboratories has been that botulinal toxin and C. botulinum are rarely, if ever, found in the feces of humans (infants or older people) not afflicted with botulism. Results of the examination in the CDC laboratory of specimens from 24 babies with infant botulism are given.