The incidence of neurotoxicity from calcineurin inhibitors varies by the organ transplanted. Akinetic mutism is characterized by the inability to perform voluntary movements and express language, without alterations in mental status. This process has been reported in neurotoxicity due to high serum levels of calcineurin inhibitors, but in rare cases, it presents as a form of tacrolimus toxicity after renal transplantation, despite normal serum levels. We report a clinical case of a renal transplant patient in whom reversible acute encephalopathy and akinetic mutism developed. Brain lesions appeared on magnetic resonance imaging, and the condition resolved after the drug was withdrawn.