Concentrations of oestradiol-17 beta, oestradiol-17 alpha, and oestrone in systemic plasma of pregnant pygmy goats (Capra hircus) remained low until about Day 60 and then rose to maximum values at Days 120-140 (parturition Day 140-145). Oestradiol-17 alpha was the predominant oestrogen. All 3 oestrogens at Days 100-130 were higher in females carrying 3 fetuses than in those carrying only one, but at Days 70-90 only oestrone values were higher. It is suggested that the feto-placental unit is the source of oestrogens during gestation in goats.