We report a rare case of posttraumatic locked-in syndrome (LIS) that appeared after an unusual three day delay. LIS was diagnosed according to clinical status and diagnostic methods (roentgenograms, computerized tomography, transcranial Doppler, electroencephalography, magnetic resonance imaging). A fourteen-year-old girl had a cervical spine injury during floor exercises that provoked LIS 72 hours after trauma. A rapid diagnosis of basilar thrombosis followed by antioedema and continuous anticoagulant therapy significantly improved the neurological status. In conclusion, posttraumatic locked-in syndrome can have sometimes a prolonged three-day delay in the clinical appearance.