In a letter the politicians claim Bishoy Armia Boulous was jailed on charges "clearly related to his religious conversion" and that he has "reportedly been harassed and physically attacked on several occasions by officials of the Tora Prison in South Cairo."
Sent to Attorney General Hisham Barakat and President el-Sisi, the letter goes on to say: "The dropping of all charges against Mr. Boulous and his swift release will help to demonstrate not only your administration's commitment to equal protection under the law...but that millions of men and women across Egypt need not fear government prosecution simply for choosing to change their religious beliefs."
Mr Boulous gained widespread attention in 2007 when he became the first known citizen to sue the Egyptian government for refusing to change the religious affiliation listed on his identification card from Muslim to Christian.
After his case became public several religious leaders called for his death.
In 2009 he was charged with blasphemy, or "defaming Islam," a charge that has since been renewed. Bishoy's next hearing is set to take place on December 28.
International Christian Concern Advocacy Director, Isaac Six, said: "This letter could not be more timely. For years Bishoy has suffered unimaginable hardship because of his courageous decision to demand a simple freedom that should be guaranteed, namely the right to change one's faith.
"We applaud these members of Congress for taking a strong stance on behalf of Bishoy and echo their call for his swift release.
"How can the Egyptian government claim to protect its citizens' rights to freedom of belief when anyone who attempts to change their faith is refused official recognition and subsequently prosecuted and tortured? The answer is, they can't."