Stiff person syndrome is a very rare disorder characterized by axial muscle rigidity, progressive stiffness mainly of the lower extremities and spontaneous, painful spasms of the abdomen, spinal or leg muscles. It is normally reported as being more common in women and affecting adults in their 4^th or 5^th decade of life. It is very rarely reported in the pediatric literature. Prompt diagnosis of this disease is of great importance due to progressive disability and pain these patients experience and most importantly due to the robust response of this disease to appropriate treatment. A case is presented of a seventeen-year-old male who was diagnosed with stiff person syndrome after one year of symptom onset. Prior to this diagnosis, multiple specialists did extensive testing and focused on symptomatic treatment without determining the underlying etiology. Numerous medical tests were performed including a CK that was mildly elevated, an MRI of the brain and spine that were noncontributory, and a positive ANA.  Various medications including baclofen and cyclobenzaprine were minimally effective. On initial presentation to neurology, the patient was dependent upon a walker for mobility, had such extreme stiffness that he had lost the ability to sit upright and was debilitated by painful muscle spasms. On examination, he exhibited rigidity of the abdomen and lower extremities, which appeared to be contracting at rest.  Diagnosis was made via EMG of the anterior tibialis, which showed continuous motor unit action potentials while at rest, indistinguishable from voluntary activity. Benzodiazepines and IVIG were initiated. The patient had such a dramatic response to treatment that he was walking independently within one day of treatment.  Glutamic Acid Decarboxylase antibody levels resulted as greater than 250 IU/mL.  The patient continues to require interval IVIG treatments to prevent symptom recurrence.