The syndrome of central diabetes insipidus (cDI) and spastic cerebellar ataxia is rare with only a few reports in the literature. We report the case of a 21-year-old patient who was diagnosed to have central diabetes insipidus at the age of 7 years and presented to us at the age of 21 years with progressive spastic cerebellar ataxia that evolved over four years. His MRI showed normal hyperintense signal from the posterior pituitary. The persistence of posterior pituitary signal in patients with cDI is unusual and is observed in the familial variety of cDI, the possible etiology in our patient. A brief review of the literature on the rare syndromic association of cerebellar ataxia and cDI has been discussed.