By Elise Viebeck - 06/13/13 04:23 PM EDT
The exchanges are the centerpiece of healthcare reform, offering a venue for the uninsured to purchase coverage using subsidies from the government.
Enrollment is scheduled to begin on Oct. 1, with coverage starting Jan. 1 of next year.
Federal health officials say they are on target, and blame Republican opposition to ObamaCare for any delays.
Roberts's bill is co-sponsored by Sens. James Inhofe (R-Okla.), John Barrasso (R-Wyo.) and Thad Cochran (R-Miss.).