The effects of prenatal exposure to anaesthetics on the early development of primordial germ cells were studied in the rat. The study consisted of 4 treatment groups: control, low and high dose of halothane + nitrous oxide and galactose as a positive control. Histological and semiquantitative studies of the gonads were performed at day 14 and 21 post coitum. They did not reveal any effect of anaesthetics on the germ cell development of the rat. In the galactose group decreased numbers of germ cells were seen as a result of general growth retardation. The results are described and discussed in view of literature data. This study was part of an experiment designed to study the effects of anaesthetics on reproduction and on pre- and postnatal development in the rat.