The results of the initial International Study of Asthma and Allergies in Childhood (ISAAC) undertaken in the mid 1990s demonstrated a substantial increase in asthma and wheeze symptoms prevalence in Irish teenagers aged 13-14 years from the 1980s. International research suggests that asthma has increased further in some countries and this study was undertaken to determine whether an upward trend in childhood asthma prevalence has continued in the Republic of Ireland in recent years. We therefore conducted two further national cross sectional studies in the same previously surveyed childhood population throughout the Republic of Ireland, one in 1998 (n=2580) and the other in 2002-3 (n=3089). We report here on rising prevalence trends of asthma (42.1% relative increase) but falling wheeze (10.4% relative reduction) prevalence in these teenage children in 2002-3.