Trigeminal sensory impairment is frequent in whiplash cases. The pathophysiology is unknown. The purpose of the present investigation was to prospectively study the trigeminal sensibility for temperature and vibration and to evaluate their relationship with the clinical symptoms. Thirty-four of 43 patients with whiplash injury were investigated through quantitative sensory tests with a mean of 6 weeks and 71 months after injury. Sensory disturbances over the trigeminal skin area persisted over the years ( r = 0.764. p < 0.000). At follow-up, a significant correlation ( r = 0.614, p < 0.000) was found between the sensory disturbances and the symptoms related to the central nervous system, whereas no significant relationship was found with the musculoskeletal symptoms. Trigeminal sensory impairment can either be explained by dysfunction in the central nervous system or by inhibitory mechanisms secondary to pain.