Robert F Bukaty/Associated Press

Departing senators are finding that the life of an ex-lawmaker can be lucrative. In recent months, several have found spots in corporate boardroom, even if they have no direct business experience in the industries wooing them.

Last week, Olympia Snowe, the former Republican senator from Maine, was named to the board of T. Rowe Price, the Baltimore investment management company that handles more than $600 billion. She joins two other senators whose terms ended in January in landing a boardroom seat.

Scott Brown, a Massachusetts Republican who briefly filled Ted Kennedy‘s seat, joined the board of Kadant, a paper- and recycling-equipment maker, on Feb. 6, just a month after his Senate term ended. (Mr. Brown was beaten at the polls by the progressive firebrand Elizabeth Warren.) He also did not remain unemployed for long, landing a position at the big law firm Nixon Peabody.

A little over a month later, on March 22, Kent Conrad, a fiscally conservative North Dakota Democrat, joined the board of Genworth Financial, a life insurance company spun off from General Electric in 2004. Mr. Conrad, Mr. Brown and Ms. Snowe are just three of the 14 senators who stepped down from the 112th Congress.

If history is any guide, other ex-colleagues will soon follow. About a third of recent former senators appear to have landed on company boards, based on an analysis corporate filings.

During last three Congressional election cycles, 43 senators have retired, quit or lost an election, according to an online database from Roll Call, one of the news outlets that closely follow the comings and goings of Beltway figures.

Some ex-senators sign onto multiple company boards. Those have included Judd Gregg, a former New Hampshire Republican and former governor of that state who was briefly in the running to serve as commerce secretary under President Obama. He sits on the boards of IntercontinentalExchange and FairPoint Communications.

John E. Sununu, who represented New Hampshire for one term and is the son of President Reagan‘s chief of staff, sits on the boards of Time Warner Cable and the medical device maker Boston Scientific. Evan Bayh, a conservative Democrat and former governor from Indiana, serves on the boards of Marathon Petroleum and Fifth Third Bancorp.

Perhaps unsurprising, there can be overlap between a lawmaker’s Senate duties and board service. Mr. Bayh, for example, had served on both the Senate’s energy and banking committees. Others oversee companies influential in their home states. Blanche Lincoln, who sat on the Senate’s energy committee, now serves on the board of Entergy, a big utility that’s a major force in her home state of Arkansas.

Other ex-senators now in the boardroom include Gordon Smith, an Oregon Republican known for helping to expand hate-crime laws to gays, helps oversee Host Hotels and Resorts; Chuck Hagel, now Mr. Obama’s defense secretary, served on Chevron‘s board after leaving the Senate in 2009; and Byron Dorgan, a North Dakota Democrat who opposed repealing Glass-Steagall serves on the board of Codexis.

Done right, serving on a corporate board can be challenging. But there’s no question the pay is good for what is, fundamentally, a part-time job.

T. Rowe Price’s board met seven times last year, for example, and acted by “unanimous consent” three other times. The executive compensation committee, which Ms. Snowe is joining, met six times.

In terms of pay, she will receive 4,200 restricted shares (worth about $302,484 at Friday’s close) and stands to collect a cash retainer of $75,000 a year, plus $1,500 for each committee meeting she attends and up to $10,000 in charitable matching contributions. In 2012, T. Rowe Price board members averaged about $280,000 each in total compensation.