The National Peace Corps Association says it's looking for about 100,000 good volunteers.
They're people who served in the overseas development program at some time in its 50-year history but later lost touch with their former colleagues.
NPCA President Kevin Quigley says there's no complete list of the 200,000 Americans who volunteered for the program, in part because key records were lost during its early days.
"When the agency was in its infancy [in the early 1960s], a lot of systems for tracking former volunteers just didn't exist," Quigley says.
The Peace Corps' first director, Sargent Shriver, resisted anything that smacked of bureaucracy, so he imposed on five-year term limit on staffers.
As result, Quigley says, the Corps lost institutional memory.
The Kennedy-era program was a low priority for the Nixon administration, which had little interest in preserving its records, he adds.
The NPCA has launched a campaign to re-connect with former volunteers who are out of the loop.
The group says it added more than 3,900 names to its list last year, and aims to identify 10,000 more in 2012.
Quigley says he's hoping to add members, raise money, and build the organization's clout when it advocates for more resources for current Peace Corps programs and support for returning volunteers.
The agency came under fire last year for allegedly failing to provide adequate support and protection for volunteers who were raped or sexually assaulted overseas.
The Peace Corps responded by creating a task force to re-examine its policies for dealing with assault victims.
The agency took a 6.5% funding cut during congressional budget battles last year, but was spared further cuts when President Obama signed an FY 2012 budget that kept Peace Corps funding level at $375 million.
(Corey Flintoff is a correspondent for NPR's Foreign Desk.)