Reid, a Democrat from Nevada, also inadvertently voted against the healthcare reform legislation in December.
After voting against the reconciliation bill Thursday when the clerk called for his vote, Reid realized his error and quickly changed his vote to "yes," CNN reported Friday.
"He did it again," someone said amid laughter.
The reconciliation fixes bill, which contained two small changes, passed the Senate on Thursday by a 56-43 vote and was sent back to the House, which approved the measure 220-207. It now goes to President Barack Obama for his signature.