The CPR's estimates are derived from median values for assets and liabilities listed on lawmakers' 2010 financial disclosure forms.
"The vast majority of members of Congress are quite comfortable, financially, while many of their own constituents suffer from economic hardships," CPR Executive Director Sheila Krumholz said.
Last year, the estimated net worth of a US senator was $2.63 million, according to the report.
"It's no surprise that so many people grumble about lawmakers being out-of-touch," Krumholz said. "Few Americans enjoy the same financial cushion maintained by most members of Congress."
Two-thirds of the Senate - 37 Democrats and 30 Republicans - reported an average net worth of $1 million or better in 2010, as did 110 House Republicans and 73 Democratic members of the lower chamber.
Financial disclosure rules allow lawmakers to value their assets and liabilities broadly, making precise evaluations of individual members' wealth difficult.
Rep. Darrell Issa, a California Republican, is the wealthiest member of the 112th Congress, with an estimated net worth of anywhere from $195 million to more than $700 million.
The richest Democrat in the House is Jared Polis of Colorado, with an estimated net worth of $143 million, the CPR said, noting that the congressman has spent $7 million of his own money on his campaigns since 2007.
Deccan Herald is on WhatsApp Channels | Join now for Breaking News & Editor's Picks