© 2021 The Japanese Society of Child NeurologyGuillain-Barré syndrome (GBS) is the most prevalent cause of acquired paralytic neuropathy in children, however, ataxia as the initial presenting sign in children is very rare. Antiganglioside antibodies are presumed to have an important role in the pathophysiology and some phenotypic correlations have been reported. Anti-GM2 antibody, unlike other antibodies, is far less detected in GBS. Here, we report a 7.5-year-old female, initially presenting with ataxia, an atypical presenting symptom in a child, is promptly diagnosed and treated successfully as GBS. Atypical history of urinary infection in our patient is an interesting aspect. The presence of isolated anti-GM2 IgM antibody and ataxia in a pediatric patient is rare. In this case report, we aim to describe an atypical initial presentation, with positive anti-GM2 antibodies, as well as review literature on isolated anti-GM2 positive pediatric GBS patients.