There is only one member of Congress who is on record as not holding a god-belief.Interestingly, the press release did not describe Rep. Stark using his own preferred self-description, as Friendly Atheist explains:
Rep. Pete Stark (D-Calif.), a member of Congress since 1973, acknowledged his nontheism in response to an inquiry by the Secular Coalition for America. Rep. Stark is a senior member of the powerful House Ways and Means Committee and is Chair of the Health Subcommittee.
When the Secular Coalition for America wrote to him, he filled in the choice that read:I had known that Rep. Stark was a Unitarian and, given their diversity of beliefs, not particularly surprised to find out that he is one of them who consider himself a "nontheist." I am annoyed, however, that the Secular Coalition for America did not think that his own self-designation was important enough to put into their press release.“I am a nontheist* and describe myself as: _________________. I also agree to allow the Secular Coalition for America to release this information to the general public.”In the blank, he filled in “Unitarian.”