Four noninstitutionalized patients, 4 months - 51 years old, presented out of 421 patients with epilepsy seen within a period of 2 years with serious symptoms of vitamin D deficiency secondary to chronic antiepileptic drug therapy. Presenting symptoms included exacerbation of seizure activity, status epilepticus, carpopedal spasms, fractures, osteomalacia, and rickets. All had low serum calcium and low vitamin D levels. Our experience supports the practice of screening patients on chronic antiepileptic drug therapy for vitamin D abnormalities.