Introduction Pernicious anemia is an autoimmune cause of Vitamin B12 deficiency, that can occur as part of polyglandular adenopathy Type 3. According to one prospective serial study, it’s incidence was 2.3%in people ≥ 60 years of age, being more common in women than men. A case of polyglandular syndrome, most likely PGA-3, is being described. She had Type 1 diabetes, Hashimoto’s thyroiditis, vitiligo & pernicious anemia. Clinical case 63 years old post-menopausal lady with Type 1 DM>15 years, Primary Hypothyroidism, Dyslipidemia, Vitiligo & Minimal NPDR. She was worked up previously for evolving cognitive defects e.g. short term memory lapses & was found to have Vit. B12 deficiency(B12-69 pmol/l, S. folate NA). Was treated e Inj. B12 replacement and got somewhat improved. Family Hx insignificant. Systemic review: NAD(No GI symptoms, candidiasis). Drug Hx: Metformin 1 gBD, Novorapid(10-10-6 units), Lantus, 16 units PM, Levothyroxine100 µg/d, Aspirin, 81 mg/d, Inj. Methyl Cobalamin-1 mg/monthly, Ferrous-folic-once daily, Refresh eye drops. Exam: Vitally stable e no postural instability. Wt 62.6(62 kgs in 2017), BMI-27.85 kg/m2 Vitiligo+ mouth, hands & feet. No hyperpigmentation. Otherwise General and Systemic exams unremarkable. Labs: HbA1c 9.8%(was 8.5%before), CBC-Hb%11.8 g/l, MCV 82.2 fl, ACR 7.68 mg/gm, Lipids(T. Cholesterol-5.91 mmols/l, LDL-3.41 mmols/l, TGs 0.95 mmols/l, HDL 2.07 mmols/l), Corrected Ca++ 2.43 mmols/l. TFTs(TSH 3.7 mIU/l, FT4 19.1 pmol/l). Rest WNL. Other Investigations: CT scan brain-normal, Short Synecthen Test negative(ACTH 4.8 pmol/l), Anti-gastric parietal cell & Anti-Intrinsic factor Antibodies strongly positive(Anti-parietal ;47.4 units-normal: 020), Anti-Intrinsic factor Abs-69.2 units-normal0-1.1 units). ECG & CXR-unremarkable. Anti-Islet cell Abs-Negative, Anti-GAD-65 Abs Highly Positive-5504.1 U/ml(0.0-5.0), S. Gastrin-30 pg/ml(0115). Anti-thyroid Abs: Anti TPO-1761 units(0-100), Anti TG-278.34 units (< 0.6 units-negative). Elective surveillance upper GI endoscopy: unremarkable apart from the finding of a 3 mms, whitish nodule in the gastric antrum. Gastric histopathology: (4 specimens). Specimen from the gastric nodule revealed mild to moderate inactive gastritis, gastric atrophy & intestinal metaplasia. Antral Bx-positive for H. pylori like organisms. Otherwise biopsies from incisura & body of stomach showed mild to moderate inactive gastritis. Gastroenterology follow-up was still awaited. Conclusions –Vitamin B12 deficiency should always be ruled out in people, esp. the elderly, having cognitive disturbances. –In the presence of other autoimmune disorders like Type1 diabetes, vitiligo etc, Vitamin B12 deficiency is most likely due to pernicious anemia, which can be proven by checking anti-gastric parietal & anti-intrinsic factor antibodies.