Rep. Charlie Norwood (search), who has suffered a breathing disorder for more than six years, underwent a lung transplant Tuesday that doctors said was necessary to save his life.

The surgery began Tuesday night in Inova Fairfax Hospital (search) in Fairfax, Va. His spokesman, Duke Hipp, said the procedure was expected to last three to six hours, and Norwood was expected to be hospitalized for two to three weeks.

The 63-year-old Georgia Republican probably will not resume his congressional duties for about three months, Hipp said.

"During the time of my recovery, I ask for healing and your prayers and comfort for Gloria and my family," Norwood said in a statement before he entered surgery. "I look forward to a successful recovery and return to my normal duties."

Norwood also asked for people to fill out organ donor cards. "It's vitally important to give life where another has ended," he said.

The fifth-term Georgia Republican was diagnosed in 1998 with idiopathic pulmonary fibrosis (search), which slowly restricts the ability to breathe. He went public with the condition last month, when it appeared surgery would be needed soon.

In recent weeks, he has voted and attended committee meetings with the aide of an oxygen canister that he carries with him.

This was the third time Norwood had reached the top of the waiting list for a transplant, but twice before doctors determined his condition was not dire enough for immediate surgery.

A dentist by trade, Norwood has taken comfort in the story of Rep. Floyd Spence of South Carolina, who served in Congress for 13 years after undergoing double-lung transplant surgery. Spence died in 2001 after surgery for a blood clot in his brain.