Objective Cognitive outcome of isolated agenesis of the corpus callosum (ACC) remains a critical prenatal situation with uncertain prognosis. Despite normal IQ and learning skills in most of the patients, the risk of specific learning disability is not clearly established. Moreover, several rare syndromes responsible for severe intellectual disability cannot be diagnosed with current prenatal genetic techniques. Only a few series have been published so far, with a small number of patients, or including both isolated and associated ACC. We describe a clinical prospective series of 46 patients with isolated ACC. Methods Between 2004 and 2013 an isolated ACC (either partial or complete) was diagnosed in 60 women referred to a regional prenatal diagnosis center. Inclusion criteria were: no other malformation on ultrasound (22 weeks) and MRI (28 weeks), no consanguinity, no familial history of developmental delay, no genetic defect on fetal karyotype or Array CGH. All patients were assessed with standardized batteries: Brunet Lézine before 3 years old, WPPSI-III at 3 and 5 years old, WISC-IV at 8 years old. Results Among 60 pregnancies, 12 abortions, one fetal death, one lost outcome, and 46 newborn (76% of the pregnancies). Among the sixteen younger children (<3 y old), one had a severe developmental delay, the others had normal developmental skills. Among the thirty older children (3 to 10 years old), one had a severe intellectual disability (Mowat-Wilson syndrome), nine (30%) had specific learning disabilities (with IQ >70), and 20 (66%) had normal IQ and learning skills. Conclusion A rare risk of a severe cognitive impairment (2/46 patients; 4.3%) cannot be excluded and must be shared with the women. Nevertheless, 30% of patients had specific learning disabilities and two thirds had a normal outcome, which is consistent with other small series of isolated ACC