The aim of this retrospective study was to compare the cyclosporine C(2) blood levels in renal transplant recipients with induction therapy, monitored on C(0) levels during the early and long-term post-transplantation periods in different French transplantation centres, to the target values recommended by the International Consensus on Neoral and used in the Mo2art study. A retrospective study was conducted by the therapeutic drug monitoring (TDM) committee of the French Pharmacological Society. Cyclosporine C(0) and C(2) concentrations from 168 renal transplant recipients were collected at different post-transplantation periods by six TDM laboratories of transplantation centres from April 2001 to April 2002. Cyclosporine blood levels were determined by fluorescence polarization immunoassay (mFPIA, AxSYM, Abbott) or enzyme immunoassay (EMIT, Dade Behring). Most patients had C(0) values in the recommended target ranges, with C(2) levels below the targets used in the Mo2art study or proposed by the International Consensus Conference, both during the early and long-term post-transplantation periods. Sixty-eight per cent of patients had C(2) below 1,500 microg/L +/- 20% in the first 2 months post-transplantation and 55% had C(2) below 800 microg/L +/- 20% in the late post-transplantation period (>1 year). Cyclosporine dose should be increased by 40% on average during the first week post-transplantation period and by 50% during the maintenance period to achieve the C(2) targets. In France, most renal transplant recipients receiving induction agents monitored on C(0) had C(2) levels below the targets recommended by the International Consensus Conference. In clinical practice, the optimal therapeutic windows for CsA monitoring based on C(2) needs to be more precisely defined, both during the early and long-term post-transplantation periods in renal transplant recipients receiving induction agents.