Previous experiments with bromocriptine suggested that prolactin plays a role in the aetiology of pseudopregnancy in goats. Serum prolactin concentration was measured in a herd of white Dutch dairy (Saanen) goats when hydrometra (a typical characteristic of pseudopregnancy) was diagnosed by ultrasound, during the spontaneous development of pseudopregnancy, and in normally reproducing goats during the breeding season. In the normally reproducing does the prolactin concentration decreased at the beginning of the breeding season. In 12 of 14 pseudopregnant goats the prolactin concentration was within the range observed in the normally reproducing goats on the day that hydrometra was diagnosed. In two goats the prolactin concentration was low during the first few weeks of pseudopregnancy and in a third it fluctuated. There was no correlation found between the concentration of prolactin and the development or the presence of a persistent corpus luteum. These results suggest that prolactin does not play a crucial role in the aetiology of pseudopregnancy in the goat.