Mycophenolate mofetil, prodrug of mycophenolic acid (MPA), is widely used for maintenance immuno­suppressive therapy in renal transplant recipients. The effect of renal graft function on MPA pharmacokinetic parameters is still controversial. The aim of this study is to investigate the impact of renal graft function on MPA pharmacokinetic during early post transplant period. Our study performed on 13 patients with severe renal impairment GFR<30ml/min,group I),and 13 patients with normal graft function (GFR >70 ml/min,group II),at steady MPA plasma level, during first month post transplant period .All patients received fix dose of MMF (1 g twice daily) in combination with Cyclosporine and steroids. MPA plasma levels were determined by validated HPLC method. MPA Area under the time-concentration curve from 0 to 12h AUC (0–12h) and apparent MPA plasma clearance (CL/f) were measured for each patient. MPA AUC (0–12h), MPA AUC (6-10h),first peak concentration (Cmax1) and secondary peak concentration (Cmax2 ) were higher in group I ,while CL/f was higher in group II (P<0.05). Trough level (C0) was similar for both groups. (P>0.05). There was a negative correlation between GFR and AUC (r=-0.422, P=0.04), while there was a positive correlation between GFR and (CL/f) (r=0.463, P=0.02). Conclusion: Our results demonstrate that MPA pharmacokinetic parameters in normal renal function patients and severe renal impairment patients are different and renal graft function correlates with total MPA AUC and apparent MPA plasma clearance, however, necessity of dose adjustment base on renal graft function need further studies.