More than three weeks after the website was launched, the administration has declined to provide information about enrollments so far.
"We have received numerous reports from Hoosiers who have been unable to enroll due to website malfunctions as well as complaints from Hoosiers who can no longer afford the new premium amounts," they wrote. "As we work to assist these constituents, it is important that we are able to provide them accurate data regarding the health insurance exchange."
The letter specifically asks for the number of applicants so far in the state of Indiana, and the number of applicants per congressional district.
Sebelius will testify next week before the House Energy and Commerce Committee in a hearing that will explore the botched rollout of ObamaCare.
The letter originated with Rep. Jackie Walorski, and was signed by Sen. Dan Coats and Reps. Susan Brooks, Larry Bucshon, Luke Messer, Todd Rokita, Marlin Stutzman and Todd Young.
Earlier in the day, Sen. Lamar Alexander (R-Tenn.) said he would propose legislation that would require weekly reports on ObamaCare enrollment numbers.