Tacrolimus is an immunosuppressive drug frequently used in solid organ transplant recipients. This drug has well-documented neuropsychiatric side effects in the literature, although emergence of psychotic symptoms is rare, being only described in a very few case reports. We present a case of a renal transplant recipient with no prior psychiatric history, who developed a severe psychosis secondary to supratherapeutic tacrolimus' blood concentrations. This case highlights the importance of clinical awareness to rare but severe neuropsychiatric effects due to tacrolimus use.