A Venezuelan-born physician who contracted the AIDS virus while treating a patient at Johns Hopkins Hospital has been denied the right to remain in the United States.

The Immigration and Naturalization Service has refused to waive the requirement that Dr. Hacib Aoun return to his home country for two years to practice medicine -- a standard policy for foreign doctors who study in the United States -- although his failing health leaves him unable to work.

"Even if I were to sit down and make up a big lie, I can't imagine anybody having more important reasons than we have to be granted the waiver," Aoun, 32, said in an interview at his Baltimore home. "It's an insensitive, coldhearted response."

However, INS officials, who made the ruling on Dec. 21, said Aoun's applications for the waiver never made it clear he had AIDS and there was only one reference to his being gravely ill. They said Aoun can ask that his case be reconsidered along with that information. In the meantime, the INS has not set a timetable for deportation.

"We're not incompassionate," INS spokesman Duke Austin said yesterday. "At the same time, there are laws in this land, and you don't waive them indiscriminately . . . . Some people have been waiting 10 years to emigrate to the United States."

Aoun's attorney, Marvin Ellin of Baltimore, called "nonsense" the INS claim of ignorance about Aoun's illness. "This man has been on national television, in the newspapers," Ellin said yesterday. "It's well-known that Hacib Aoun has AIDS. It's not as if it was hidden from public notice."

For Aoun and his wife Patricia, who is also a physician, the ruling brought the latest uncertainty to a tragedy that has shattered and overwhelmed their lives.

In effect, Aoun is now an illegal resident, his doctor-in-training visa no longer valid. And, unlike immigration cases involving the nonmedical community, the fact that Patricia Aoun is an American citizen does not give Hacib Aoun an advantage in obtaining permanent residency status. "Sometimes we get the idea somebody up there doesn't like us," Aoun said, pointing upward with a laugh.

Before he was diagnosed with AIDS, Aoun, a cardiologist, had received the honor of chief resident at Johns Hopkins, and by all accounts was a brilliant, dedicated young doctor. Now he is a patient suffering from a disease that, he said, "touches every single aspect of your life and can kill you in such ugly ways." Since September he has been hospitalized four times, a total of two months, for infections and other complications.

His treatment includes chemotherapy at the University of Maryland Hospital and monthly visits to the National Institutes of Health, where he is taking AZT, a drug that can slow fatal infections resulting from AIDS in some patients. AZT is unavailable in Venezuela, Aoun said.

Although it would not be confirmed until almost four years later, the nightmare began in February 1983 while Aoun was trying to save the life of a teen-age leukemia patient. It was one of Aoun's rare nights off, but he returned to the hospital to see the boy. "I felt very committed to trying to make him feel better," he said, "because at times he really looked like he was going to make it."

The boy, who had undergone a bone marrow transplant and received numerous transfusions, suddenly began vomiting blood; Aoun collected a small sample in a glass tube for a blood count. The tube shattered, however, and its jagged end drove deep into Aoun's finger. The boy died several weeks later.

Three weeks later, Aoun became ill with fevers, fatigue and swollen glands. At the time, however, the AIDS virus was extremely rare and there was no blood test for the infection. It was not until November 1986, when Aoun again suffered fatigue and weight loss, that he and his doctor recalled the 1983 incident and tested for the AIDS virus. Later, a stored sample of serum from the leukemia patient was tested, with results suggesting the patient's blood had been contaminated with the virus.

Aoun, who sued Johns Hopkins Hospital for $35 million for libel, slander and breach of confidentiality regarding his infection, reached a private settlement with the hospital last month. That fight over, he said he is reluctant to spend his remaining energy fighting the INS.

Aoun sat on a flowered couch in his sunlit living room, fingering a branch on the Christmas tree as he talked. Aoun said he decided to become a doctor when he was 12.

"What made me feel I wanted to be a doctor was polio," he said. "It was so aggressive in my country in 1954 and 1955. It left many kids my age with permanent damage. There were a couple I saw every day in class. I was frustrated because there were things I could say to make them feel better, but nothing I could really do."

At the University of Costa Rica, he was second in his medical class of 150. He interned at Vanderbilt University Hospital, and in June 1982, began his residency at Johns Hopkins, where he eventually met his wife. They married in 1985.

Before he became ill, Aoun was doing research in valvular heart disease and revisited Costa Rica each year to give teaching conferences to medical students. He also cowrote two books that are used as texts in Central and South America. The Aouns planned to do further research together. "We had so many dreams," he said. "From the very first day, we asked ourselves, 'Why?' because our dreams were so special. We had a life directed with so much purpose, you know, alive with meaning and purpose and direction."

Aoun said he can't avoid thinking that his desire to become a doctor inadvertently led to what will almost certainly be an early death.

But, he said, "I miss my work tremendously. I miss my patients from East Baltimore -- they were nice humble people with real problems.

"I love medicine," he said. "I still do. In spite of everything."