This report describes the prevalence and trends of neural tube defects (NTD) in Australia during the past decade. An estimated prevalence of NTD among pregnancies is presented based on the information from states that collect near complete data on NTD. Characteristics and outcomes of the births and pregnancy characteristics of the mothers are presented for the period 1998-2005. The purpose of compiling this national report is to provide baseline prevalence of NTD, prior to the implementation of mandatory folic acid fortification of bread flour in September 2009. This report is produced by the AIHW National Perinatal Statistics unit and will be of interest to staff of state and territory birth defect registers and perinatal data collections, health professionals, health and welfare planners, policy makers, researchers, students and consumers.