We aimed to develop an accurate and convenient LSS for predicting MPA-AUC0–12hours in Tunisian adult kidney transplant recipients whose immunosuppressive regimen consisted of MMF and tacrolimus combination with regards to the post-transplant period and the pharmacokinetic profile. Each pharmacokinetic profile consisted of eight blood samples collected during the 12-hour dosing interval. The AUC0–12hours was calculated according to the linear trapezoidal rule. The MPA concentrations at each sampling time were correlated by a linear regression analysis with the measured AUC0–12. We analyzed all the developed models for their ability to estimate the MPA-AUC0–12hours. The best multilinear regression model for predicting the full MPA-AUC0–12hours was found to be the combination of C1, C4, and C6. All the best correlated models and the most convenient ones were verified to be also applicable before 5 months after transplantation and thereafter. These models were also verified to be applicable for patients having or not the second peak in their pharmacokinetic profiles. For practical reasons we recommend a LSS using C0, C1, and C4 that provides a reasonable MPA-AUC0–12hours estimation.