OBJECTIVE: To assess the performance of TexKat, the largest Hurricane Katrina Medicaid Emergency Waiver, in providing care to asthmatic children. METHODS: Medicaid enrollment and encounter data for 2004 and 2006 from Louisiana and Texas were analyzed in a pre-post comparison. Changes in utilization by children in the waiver were compared to changes in utilization by children in Medicaid in three control groups: children in Louisiana counties that were designated as a disaster assistance area but who were not displaced; children in Louisiana counties that were not designated as a disaster assistance area, and children in Texas. The analysis included prescriptions for controller and quick-relief medications as well as encounters in inpatient, emergency, outpatient, and office settings. RESULTS: The sample proportion of TexKat enrollees who had a prescription filled for controller medications fell from 0.37 to 0.28 between 2004 and 2006. By contrast, the sample proportions for the three control groups were relatively unchanged or increased. The inferential analysis indicated that the 2004-2006 change in proportions for the TexKat group differed from the changes for each of the three control groups (p-value < 0.001). For office and emergency department visits, the 2004-2006 decreases in both the proportion of subjects with a visit and the average number of visits for the TexKat group were greater than the changes for the control groups (p-value < 0.001). CONCLUSIONS: While TexKat appears to have largely been successful in preventing extreme utilization disruptions, the analysis suggests that children in the program may have received inadequate care.