The primary objective of this study is to collect safety information on rabeprazole 10 mg and 20 mg in the treatment of gastroesophageal reflux disease (GERD) in children aged 12 to 16 years. The secondary objectives are to assess the efficacy of rabeprazole on the improvement of the symptoms of GERD and to explore the relationship of symptom relief to dose received, based on symptom frequency and severity, antacid use, and quality of life (QOL) measures.