Gatundu South MP Moses Kuria has been ordered to pay Martha Karua Sh 6.5 million for defamation.
The High Court made the ruling in a matter where Kuria claimed the NARC leader procured witnesses to fix Deputy President William Ruto during ICC cased.
Karua demanded Sh20 million from the MP in damages for defamation.
She told the court in September that despite demanding an unconditional apology from Kuria, he went ahead and repeated the same claims at Parliament Buildings.
"The claims are scandalous, malicious, unwarranted and lowered my dignity among right thinking members of the society,” she said.
Kuria first made the claims during a rally in Kapsokwony in Bungoma County on September 21, 2015.
He claimed that he met with Karua and other leaders at Galileo in Westlands area to scheme on how to recruit fake witnesses to testify against Ruto.
The MP did not defend the suit.
Ruto and President Uhuru Kenyatta faced crimes against humanity following the 2007-2008 post-election violence, but the matter was dropped.