We present four incidental cases that developed partial myelitis following the administration of hepatitis B vaccine in 1998. The first two cases, a 33-year-old man and a 42-year-old woman developed progressive sensory symptoms without motor involvement within 4 weeks following the vaccination. Their magnetic resonance imaging (MRI) disclosed similar lesions consistent with myelitis at their cervical spinal cord. A comparable inflammatory lesion was seen at the T9-T10 levels of the spinal cord in the third case, who was a 40-year-old woman presenting with numbness in her legs and urinary retention following the vaccination. The fourth case who was a 42-year-old woman, presented with sensory symptoms in her left extremities, which developed 3 months after the vaccination. Her MRI showed a hyperintense lesion at C6. She also had two tiny lesions in her cranial MRI. In all cases, there was no history of preceding infections and no clinical evidence suggestive of any other disorders that may cause myelopathy. All patients recovered completely within 3 months with the exception of the third patient who developed new neurological symptoms after 12 months. Similar clinical and imaging presentation of myelitis following hepatitis B vaccination within a 1 year period with no other demonstrable clinical and laboratory evidence for any other disorder raise the probability of a causal link between these two events.