The recovery of the mechanosensitive and thermosensitive afferent fibres in the lingual branch of the trigeminal nerve has been studied using electrophysiological techniques in cats after nerve section without repair or after section followed by nerve repair 12 weeks later. In the unrepaired group, recovery was permitted for 24 weeks, and after delayed repair there was a further recovery period of either 12 or 24 weeks. The characteristics of the regenerated fibres were then investigated, and data were also compared with those from normal control animals and from animals which had undergone immediate nerve repair. The results revealed only small differences between the repaired and unrepaired groups and it is concluded that delayed repair of a clean transection site results in only slightly better recovery than leaving the nerve unrepaired. It is also concluded that a 12-week delay before repair has little detrimental effect.