The presence of severe and mild neurotoxicity in our pediatric renal transplant recipients treated with tacrolimus was determined by chart review (severe neurotoxicity) and patient survey (mild neurotoxicity). 14 patients were studied (mean age 15 yr, 5 month, +/- 4.4 yr). 1 patient experienced seizures, felt to be related to malignant hypertension. No other episode of severe neurotoxicity was documented. Most patients (12/14) reported at least one mild neurologic symptom, and half stated their symptoms were present at least 'most of the time'. The most frequent complaints were myalgias (7/14, 50%) and tremors (7/14, 50%) followed by fatigue (5/14, 38%). Severe neurotoxicity may be relatively infrequent in pediatric renal transplant patients treated with tacrolimus. Milder neurologic complaints may be commonly seen in this population, but in general are not severe enough to cause discontinuation of tacrolimus.