Experiments were performed with three dogs, Canis familiaris, trained in human scent discrimination (American Kennel Club utility obedience test), to evaluate whether the dogs could distinguish the scent of their handler from the scent of other humans, irrespective of the body part from which the scent had been collected. The dogs were successful at distinguishing scent obtained from the hand of their handler from that from the hands of strangers, but could not similarly distinguish their handler's scent when it was obtained from the crook of his arm. These results suggest either that there is no such thing as an individual human odour or that dogs trained with standard methods do not spontaneously identify individual odour components of scents taken from different parts of the body. The results also call into question the practice of using dogs to identify individuals from scented objects in law enforcement, unless the dogs used can be shown to be capable of performing discriminations of the type unsuccessfully attempted by the animals in the present study. © 1991 The Association for the Study of Animal Behaviour.