Vitamin B12 deficiency causes haematological, gastrointestinal, psychiatric and neurological diseases. Subacute combined degeneration (SCD) of the spinal cord, characterised by degeneration of the lateral and posterior columns, is often found due to vitamin B12 deficiency. We report SCD occurring in a 57-year-old man who presented with a 2.5-month history of gradually progressing tingling in the fingers and toes and neck ache. Laboratory data revealed vitamin B12 deficiency and magnetic resonance (MR) imaging of the cervical spinal cord demonstrated abnormal hyperintense signal changes on T2-weighted imaging of the posterior columns. In our case, follow-up MR imaging findings correlated well with clinical outcome after treatment with vitamin B12 supplements. Neurological symptoms in vitamin B12 deficiency are frequent. Early spinal MR imaging assists in the early diagnosis and treatment of the disease.