The aim of this paper is to provide a summary of clinical findings regarding the safety of tacrolimus in pregnancy. From 1992 to 1998 data were collected on 100 pregnancies from 84 mothers who received tacrolimus systemically; 83 cases of solid organ transplantation, and 1 case of Behçet's disease. Maternal mean age at conception was 28 years and pregnancy outcome was live birth in 68%, spontaneous abortion in 12%, induced abortion in 12%, stillbirth/perinatal death in 3%, ongoing pregnancy in 2%, and lost to follow up in 3%. Fifty-nine percent of the neonates were delivered prematurely (< 37 weeks of gestation). Birth weight was appropriate for the gestational age in 90% of the cases. Malformations occurred in 4 neonates: case 1, meningocele and urogenital defects; case 2, alcoholic embryopathy; case 3, ear defect, cleft palate and hypospadia; case 4, multicystic dysplastic kidney. There was no consistent pattern of malformations and 2 mothers subsequently delivered a healthy neonate while on tacrolimus therapy. Nearly 70% of pregnancies following systemic tacrolimus administration resulted in a favourable outcome without any significant effect on intrauterine growth. The incidence of malformations was similar to that reported with other immunosuppressants in transplant recipients.