Long-term follow-up five to 13 (mean seven years) of 13 cases of whiplash-shaken-infant syndrome (WSIS) demonstrated long sign-free intervals. Full clinical appearance of neurological deficits takes four months for the interruption of brain growth, six to 12 months for lesions of the central nervous system long pathways, up to two years for epilepsy, and three to six years for behavioural and neuropsychological signs. In our series, WSIS occurred at a mean postnatal age of 5.5 months and caused intracranial, retinal and preretinal haemorrhages, intracranial haematomas, oedema, contusional tears, and developmental disturbances interfering with the growth and differentiation of neural tissue and with synaptic stabilisation. These mechanisms account for the long sign-free interval that makes its impossible to formulate a precise and final neurological prognosis before the age of school entrance. Only one of our patients seems to have remained normal even several years after the shaking.