The Iraq-based People's Mujahidin "strongly condemned" what it described as "efforts by the Iranian regime and its agents to blame" it for the blasts.
"These claims are sheer lies," a spokesman said.
"The mullahs' objective in churning out these lies is to create mischief between the People's Mujahidin Organisation of Iran and the Iraqi government.
"These efforts reflect the desperate state of the mullahs' regime in the face of the unprecedented public response to the Iranian resistance's calls for a nationwide boycott of the sham presidential election on 17 June."
The bombings came just days ahead of a presidential election.
Iran blamed "terrorists" and Arab separatists sheltered by US troops in neighbouring Iraq.
Former fighters of the People's Mujahidin remain cantoned in a camp northeast of Baghdad under US supervision, having been disarmed under an agreement reached following the US-led invasion of Iraq in March 2003.