We propose a model to calculate individualized Neoral doses based on individual oral clearance (CL/F)(i) and AUC((0-12h)) values. The equation proposed by Dr. Ke-Hua Wu (2005), was employed to calculate the CL/F(i) = 28,5 - (1.24*POD) - 0.252*(TBil-11) + 0,188*(Weight o-58) -0,191*(Age-42) - 2,42*INHI - 0,212*(HCT-28), where CI/F = (L/h), POD = postoperative days, Bil.T = total bilirubin level (umol/L), CBW = in kilograms, age = in years, INHI = concurrent metabolic inhibitors present (1) or absence (0), and HCT = hematocrit percentage. The AUC((0-12h)) was calculated from the C(2) value using the equation AUC((0-12h)) = 815,578 + 4,44696*C(2), derived from the linear correlation observed in earlier work at Clinica Las Condes Hospital. The studied population were 30 kidney transplanted children at Luis Calvo Mackenna Hospital, between 2002 and 2006, who were divided into 2 similar groups according to accurate C(2) sampling time collections. The control group 1 was composed of 13 patients of age 9.85 +/- 4 years whose samples were collected correctly. Group 2 was composed of 17 patients of age 10.43 +/- 6 years with 252 C(2) samples, which were obtained at medical control. All patients were under oral treatment with prednisone, azathioprine, nifedipine, and Neoral administered twice day according the weight of the patient and the C(2) level. Relating Neoral administered doses to calculated doses according to the proposed model, the control group showed a linear correlation coefficient r = 0.924; r(2) = 85.4%; (P < .05), and group 2, r = 0.54; r(2) = 29.1 (P < .05). The proposed model to calculate Neoral doses had a predictive value of 85.0% when C(2) samples were collected correctly.