The lawmakers, 10 of the chamber's 17 women, urged the secretary general to publicly urge the military regime to end human rights abuses, "eliminate rape as an instrument of war" and bring violators to justice.
"We must not allow this regime to continue to commit such dire crimes unabated while the people of Burma continue to suffer," they wrote in the letter, which was dated April 9.
The senators urged Ban to call on the junta in Myanmar, which Washington refers to as Burma, to "release Aung San Suu Kyi and all political prisoners immediately and unconditionally."
They also pressed him to ask the military to "abandon plans" to hold elections in 2010 under a much-criticized new constitution approved in May 2008, after Cyclone Nargis devastated southern parts of the country and left 138,000 people dead or missing.
"The upcoming election is based on a unilaterally drafted constitution that violates international law and entrenches gender discrimination in Burma," the US senators wrote.
"The constitution in its current form precludes women from holding high-level government positions and attempts to give amnesty to the military junta and thus deny access to justice for the victims of the military regime's systematic sexual violence against ethnic minority women," they said.
And they said Ban should urge the junta to "facilitate" a "dialogue towards national reconciliation" grouping Nobel Peace Laureate Aung San Suu Kyi, the military regime, and ethnic nationality representatives.
Myanmar has been ruled by the military since 1962 and is under tough sanctions by the US and European countries because of its human rights records and continued detention of Aung San Suu Kyi, whose opposition party won a landslide victory in 1990 elections that the junta set aside.
The letter was signed by Senators Dianne Feinstein, Kay Bailey Hutchison, Patty Murray, Olympia Snowe, Blanche Lincoln, Maria Cantwell, Susan Collins, Barbara Boxer, Amy Klobuchar, Barbara Mikulski, and Lisa Murkowski.