Objective: The authors analyze the occurrence of grade repetition and inattention in children diagnosed with neurofibromatosis type 1 (NF1). Method: The participant group consisted of 310 patients with NF1 and a control group of 242 individuals. The number of grade repetitions for each participant during his or her time in elementary, middle, and high school was noted and the inattention score was calculated from the Barkley's ADHD Clinic Parent Interview form. Results: Fifty-three percent of NF1 patients versus 25% of the controls had increased grade repetition, P2 (1) = 27.41, p less than 0.0001, and 67% of NF1 patients versus 14% of controls were found to be inattentive, 2 (1) = 27.41, p less than 0.0001. Repetition mainly affected kindergarten and first-grade levels and the inattention score significantly correlated with grade repetition prevalence in NF1 patients (r[superscript 2] = 0.7429, p less than 0.0004). Conclusion: Grade repetition is a frequent complication in NF1 and correlates with inattention in individuals with this disease. (Contains 2 figures and 1 table.)