Simultaneous pancreas-kidney (SPK) transplant recipients are at high immunological risk of rejection. Antibody induction is beneficial but lymphocyte-depleting therapy is associated with a high incidence of side-effects. We performed a historical controlled trial to compare OKT3 versus anti-CD25 antibody (basiliximab) induction therapy with regard to patient, kidney and pancreas survival, as well as to examine for any differences in acute rejection, graft function, and infective complications. Twenty-eight consecutive SPK transplants were performed at the Monash Medical Centre between December 1997 and November 2001. Anti CD3 monoclonal antibody (OKT3) was used prior to March 2000 (n = 12) and basiliximab was used after (n = 16), both in combination with cyclosporin, mycophenolate, and prednisolone. A retrospective comparison of outcomes was performed. At 6 months, patient (100 vs 100%), kidney (91.7 vs 91.7%) and pancreas (75 vs 83.3%) survival were similar in the OKT3 and basiliximab groups, respectively. A minority of subjects in each group remained free from rejection (42% basiliximab vs 25% on OKT3, P = NS). Renal function was superior in the basiliximab group (mean calculated creatinine clearance 79.4 +/- 11.9 vs 54.5 +/- 15.9 mL/min for basiliximab vs OKT3, P < 0.001). The incidence of major opportunistic infection was lower in basiliximab-treated patients (9 vs 50% in the OKT3 group, P = 0.033). Basiliximab was associated with similar 6-month patient, kidney and pancreas survival, superior renal function and less opportunistic infection as compared with OKT3 induction therapy in SPK transplants. Basiliximab is at least as effective and is safer than OKT3 for induction therapy in SPK transplantation.