Tied for second are the National Rifle Association of America, which was fourth last year, and the National Federation of Independent Business, which was third last year.

"Let's put this into perspective," Kenneth Bricker said. "We're talking about an unscientific survey of 400 individuals. The real story here is that AIPAC, with the lowest operating budget of the so-called top 10 lobbies, continues to have a perennial place at the top of the list."

AIPAC's annual budget is $16 million, Bricker said, while AARP's budget is $540 million and the NRA's is $137 million.

The questionnaire was mailed to 2,773 people, including every member of Congress, Capitol Hill staffers, senior White House aides and professional lobbyists. Fifteen percent, or 427, of the surveys were returned.

Respondents were asked to assess, on a scale of 0 to 100, the political clout of 114 trade associations, labor unions and interest groups.