The ability of 44 children with a severe unilateral sensorineural hearing loss to localise sound in the horizontal plane, has been compared with that of 40 subjects with normal hearing. It was found that the normally hearing group had no difficulty localising sounds in contrast to the majority of hearing-impaired children. None of the children with a hearing loss localised a 500-Hz pure tone as well as the normally hearing group, but 1 was able to localise a low-frequency noise stimulus and 9 a high-pass noise as accurately as those with normal hearing. Covering the pinna in 22 of the hearing-impaired children affected the ability of those who localised the high-pass noise normally more than the remainder of this group. This suggests that better use of pinna information was an important factor in their superior performance.