Plasma 25-hydroxyvitamin-D(25-O.H.D.), Ca, P, and alkaline-phosphatase levels were determined in three separate periods during pregnancy in 14 Caucasian mothers, 23 vegetarian Asians, and 16 non-vegetarian Asians. Non-pregnant women from the same group were used as controls. The expected steady rise in alkaline phosphate during pregnancy due to increase in the placental isoenzyme, and the fall in total Ca due to haemodilution, were noted. No appreciable changes in 25-O.H.D. levels occurred, but throughout pregnancy the levels in the vegetarian Asians were lower than in the other two groups. The same analyses were made in maternal and cordplasmas in some of these patients. The babies' 25-O.H.D. levels averaged 87% of their mothers'. There was no clear evidence that pregnancy as such led to increased vitamin-D requirement in any case of these groups.