Summary: Of nearly $35 billion in child support payments owed nationwide under the Child Support Enforcement Program, more than $27 billion remained uncollected at the end of fiscal year 1992. During that year, more than 5.7 of the 8.5 million noncustodial parents owing child support made no payment on the amount owed. Eleven of 16 states GAO reviewed routinely report child support payment information to credit bureaus; five states report information only at the request of credit bureaus. Most of the states that routinely report usually report only delinquent noncustodial parents. These states generally report to all three major credit bureaus information that is less than 30 days old, and few states have had problems categorizing child support payments in an automated and standardized format for the credit bureaus. The costs to start up and run credit bureau reporting systems appear to be nominal. The effects of credit bureau reporting on increasing collections have not been widely evaluated by the states GAO reviewed, but completed studies and comments by state and credit grantor officials suggest that credit reporting is helping with enforcement. One state suggested that its main benefits will appear over time as creditors deny credit to delinquent parents.