138 Indian patients with megaloblastic haemopoiesis were studied. All were lifelong vegetarians. The diagnosis was nutritional cobalamin deficiency in 95 and pernicious anaemia in 20; only 4 patients had folate deficiency. A third had intestinal malabsorption, 20 had features of osteomalacia, and 87 were iron deficient. Tuberculosis was diagnosed in 17. Cobalamin deficiency may have contributed to these complications via intestinal malabsorption and impaired bacterial killing of phagocytosed bacilli by cobalamin-deficient macrophages. The frequency of pernicious anaemia was the same in Indian subjects as in Caucasians.