AimWhen administering tacrolimus, therapeutic drug monitoring is recommended because nephrotoxicity, an adverse event, occurs at supra‐therapeutic whole‐blood concentrations of tacrolimus. However, some patients exhibit nephrotoxicity even at the recommended concentrations. Therefore, establishing a therapeutic range of tacrolimus concentration for the individual patient is necessary to avoid nephrotoxicity. This study was aimed at developing a model for individualised prediction of nephrotoxicity in patients administered tacrolimus.MethodsWe collected data, such as laboratory test data at tacrolimus initiation, concomitant drugs, and tacrolimus whole‐blood concentration, from medical records of patients who received oral tacrolimus. Nephrotoxicity was defined as an increase in serum creatinine levels within 60 days of tacrolimus initiation. We built 13 prediction models based on different machine learning algorithms: logistic regression, support vector machine, gradient‐boosting trees, random forest, and neural networks. The best‐performing model was compared with the conventional model, which classifies patients according to the tacrolimus concentration alone.ResultsData from 163 and 41 patients were used to construct models and evaluate the best‐performing one, respectively. Most of the patients were diagnosed with inflammatory or autoimmune diseases. The best‐performing model was built using a support vector machine; it showed a high F2 score of 0.750 and outperformed the conventional model (0.500).ConclusionA machine learning model to predict nephrotoxicity in patients during tacrolimus treatment was developed using tacrolimus whole‐blood concentration and other patient data. This model could potentially assist in identifying high‐risk patients who require individualised target therapeutic concentrations of tacrolimus prior to treatment initiation to prevent nephrotoxicity.