This Statistical Brief presents data from the Healthcare Cost and Utilization Project (HCUP) on changes in the rates of potentially preventable hospital admissions and their associated total hospital costs. It updates statistics previously reported for the 1997 through 2004 time period. Admission rates for selected chronic and acute conditions in adults and children for 2005 through 2010 were developed using the Agency for Healthcare Research and Quality (AHRQ) Prevention Quality Indicators (PQIs). The conditions examined for adults aged 18 years and older were related to diabetes, circulatory diseases, chronic respiratory diseases, and select acute conditions (bacterial pneumonia, dehydration, and urinary tract infection). The conditions examined for children younger than 18 years were diabetes, asthma, gastroenteritis, and urinary tract infection. All differences between estimates noted in the text are significant at the 0.05 level or better.