This report presents the results of our review to determine whether U.S. Customs and Border Protection has established adequate controls and effective oversight of contract workers providing support services to Secure Border Initiative programs. U.S. Customs and Border Protection has not established adequate controls and effective oversight of contract workers responsible for providing Secure Border Initiative program support services. Because of the Department of Homeland Security's aggressive Secure Border Initiative program schedule coupled with shortages of government program managers and acquisition specialists, in the early years of the Secure Border Initiative program, U.S. Customs and Border Protection relied on contractors to fill the skills gap and get the program underway. U.S. Customs and Border Protection continues to rely heavily on contract personnel, who comprise more than 50% of the Secure Border Initiative workforce. Furthermore, U.S. Customs and Border Protection has not clearly distinguished between roles and responsibilities that are appropriate for contractors and those that must be performed by government employees. U.S. Customs and Border Protection also has not provided an adequate number of contracting officers technical representatives to oversee support services contractors performance. As a result, contractors are performing functions that should be performed by government workers.