Asrat Woldeyes, 70, a British-educated Ethiopian surgeon who was a longtime champion of democracy and opponent of Ethiopia's authoritarian government, died May 14 at a hospital in Philadelphia. He had a heart ailment.

Dr. Woldeyes, an advocate for the poor and underprivileged, was president of the All-Amhara Peoples Organization, a group that denounced violence as a tool of political change.

He was a thorny critic of Prime Minister Meles Zenawi, attacking government policies that called for the establishment of autonomous regions established along linguistic and ethnic lines.

Dr. Woldeyes, a surgeon, was the dean of Ethiopia's medical school and had pioneered medical education in his poor but proud state. He also had served as the personal physician of the late Emperor Haile Selassie.

Dr. Woldeyes had been imprisoned, but he was released last year to seek medical treatment abroad. After undergoing treatment in Britain and Texas, he settled in Philadelphia about a month ago where he had relatives.

He had served a five-year prison term in an Ethiopian jail on charges of encouraging armed insurrection in two speeches.

Dr. Woldeyes was awaiting trial on charges of treason when he was temporarily released from jail in December.

His troubles began in 1992 after he met with Rep. Harry A. Johnston II (D-Fla.) and made critical remarks about Ethiopia's left-wing strongman Meles Zenawi, pointing out that the leader had broken promises to bring democracy to Ethiopia.

Three days after the meeting, Dr. Woldeyes was arrested for "inciting rebellion."

His trial was something of a farce. Witnesses against the surgeon recanted their stories, claiming government authorities had pressured them to lie. Despite this, Dr. Woldeyes was sent to jail after refusing to stop speaking out for democracy.

While in jail, he became what one Washington Post op-ed piece called "Ethiopia's most popular public figure and its symbol of democracy." The 1996 piece, by David E. Steinman, went on to say that Dr. Woldeyes would "probably be president of Ethiopia today had not Meles imprisoned him before the election."

Amnesty International championed Dr. Woldeyes's cause, calling him "a prisoner of conscience who should be released immediately."

In 1998, after pressure by both private citizens and U.S. government officials, the State Department was able to officially welcome "the humanitarian gesture" of the Ethiopian government in releasing Dr. Woldeyes.