Kenny Syndrome, also known as the Kenny-Caffey Syndrome, is a condition manifested by dwarfism, delayed closure of the anterior fontanelle, cortical thickening of the tubular bones, hypocalcemia due to hypoparathyroidism, and ocular abnormalities including nanophthalmia and hypermetropia. Our patient is a Caucasian male who presented at 3 weeks of age with hypocalcemic seizures. Hypocalcemia was accompanied by hyperphosphatemia and hypomagnesemia, and other electrolytes were normal. Family history was negative and parental calcium levels were normal. Despite several doses of parenteral magnesium sulfate, hypomagnesemia persisted necessitating the institution of chronic oral magnesium replacement along with oral calcium and vitamin D. When serum magnesium levels normalized, calcium supplementation could be discontinued. Parathyroid hormone levels were subnormal during hypocalcemia. Magnesium balance studies were performed at 4 months and 16 months of age, and did not localize the source of hypomagnesemia either to defective gut absorption or to excessive urinary losses. The patient has failed several attempts to discontinue magnesium therapy. At 1 year of age he was diagnosed with strabismus and myopia, and was treated with surgery and corrective lenses. At the same age he developed severe linear growth failure. Skeletal survey and endocrine evaluation were negative. His bone age was delayed at 9 months when he was 21 months of age, and his anterior foantanelle was still widely open. At 2 9/12 years he was started on recombinant growth hormone therapy. His growth velocity improved from less than the 5th percentile for age to the 50th percentile for age. At 5 years of age his fontanelle was still open, his growth rate was normal, and an ophthalmologic examination revealed the presence of nanophthalmia, hyperopia, and small corneas, consistent with Kenny Syndrome. Repeat skeletal survey showed the characteristic tubular stenosis dysplasia. Currently at 6 1/2 years of age he has normal intelligence and linear growth rate, his bone age is 4 1/2 years, and he remains on magnesium and vitamin D replacement therapy. We believe that this patient demonstrates that the defect producing hypoparathyroidism in the Kenny Syndrome may be primary hypomagnesemia. In addition, growth hormone may be efficacious in treating the dwarfism of this syndrome.