In a retrospective study (1985-1989) based on data from the Centre for Reproductive Medicine in Brussels, a total of 23 ectopic pregnancies (2.24%) occurred after 3800 embryo, zygote or gamete transfers. This number was low compared with the data published elsewhere. Tubal damage was a major risk factor towards developing an ectopic pregnancy after in-vitro fertilization and embryo transfer. The number of ectopic pregnancies after the association of clomiphene citrate and human menopausal gonadotrophin (HMG) was significantly higher in patients with tubal (7.8%) and non-tubal indications (2.1%) compared with those stimulated with gonadotrophin-releasing hormone (GnRH) and HMG (2.18% and 0.84%, respectively). The number of replaced embryos was not associated with the rate of ectopic pregnancy and neither did transfer technique (intra-uterine or intra-Fallopian transfer) influence the ectopic pregnancy rate.