As individuals age, some become incapable of managing their personal and financial affairs. To protect these individuals, state laws provide for court appointment of guardians, who may be professionals or family members, to protect the incapacitated person's personal and/or financial welfare. State and local courts are responsible for overseeing guardians. In addition, federal agencies may appoint a representative payee, in some cases, the guardian, to manage federal benefits on behalf of incapacitated adults. Previous GAO reports have found that poor communication between state courts and federal agencies may allow guardians to continue abusing their victims. GAO was asked to (1) verify whether allegations of abuse by guardians are widespread; (2) examine the facts in selected closed cases; and (3) proactively test state guardian certification processes. To verify whether allegations are widespread, GAO interviewed advocates for seniors and reviewed court documents. To examine closed criminal, civil or administrative cases with a finding of guilt or liability in the past 15 years, GAO reviewed court records, interviewed court officials, attorneys and victims, and reviewed records from federal agencies. To test state guardian certification, GAO used fictitious identities to apply for certification in four states. GAO's results cannot be projected to the overall population of guardians or state certification programs.