This report was prepared in response to a mandate from the California State Legislature to analyze how much of the $14.4 billion in child support arrears owed statewide in March 2000 was realistically collectible. Child support arrears had grown dramatically in California during the prior decade and state legislators were concerned about their collectibility. The Urban Institute estimated that $3.8 billion, or 26% of the $14.4 billion, would be collected over 10 years. The reason that so little arrears are likely to be collected is that most of the arrears are owed by individuals who owe more than $20,000 in arrears and have relatively low incomes.