The aim of the study was to determine whether immunosuppressive agents used in renal allograft recipients are teratogenic or otherwise associated with pregnancy outcome. The study population consisted of 38 renal allograft recipients treated with combinations of prednisone, azathioprine, cyclosporin A, and tacrolimus attending our Hypertension in Pregnancy Clinic. The 48 live offspring of 73 pregnancies in this group were evaluated for major congenital malformations and mild errors of morphogenesis. Findings were compared with those in 48 offspring of 41 women with primary renal disease not treated with immunosuppressive drugs. Pregnancy outcome parameters were also compared between the study and control groups in the perinatal period and on a long-term basis (2–7 years after birth). Two major anomalies (4.2%), subcoronal hypospadias and rudimentary thumb, and 10 mild errors of morphogenesis (20.8%) were detected in the study group. These rates did not differ significantly from those in the control group (4.2% and 16.6%, respectively). Pregnancy outcome was worse in the renal transplant patients than in the women with primary renal disease in terms of prematurity (60% vs. 21%, P = 0.001), growth restriction (52% vs. 17%, P = 0.001), and hospitalization in a neonatal intensive care unit (35% vs. 6%, P = 0.01). In conclusion, the similar prevalence of major anomalies and mild errors of morphogenesis in offspring of the renal transplant patients and the women with primary renal disease suggests that immunosuppressive therapy is not a teratogenic factor. It may, however, be associated with worse pregnancy outcome. © 2002 Wiley-Liss, Inc.