Dr. Roberto Lazarus, the ambassador of Honduras to the United States, Canada and the Organization of American States, died at Georgetown University Hospital Tuesday following a heart attack.

Dr. Lazarus' career combined medicine and diplomacy. He was born in San Juancito, Honduras, and educated in Tegucigalpa, Honduras, and in Germany, where he earned a doctorate in medicine and a surgery at the University of Hamburg.

He taught medicine at the Central University of Honduras and was superintendent of the medical department of the United Fruit Co. He later served as his country's minister of public health.

He began his diplomatic career in 1958, when he was appointed the Honduran ambassador to France. He returned home two years later and was subdirector of the Honduran Social Security Institute. He then became director of the San Felipe General Hospital in Tegucigalpa.

From 1965 to 1968, he was the Honduran ambassador to West Germany. He returned to Germany as ambassador from 1973 to 1974 after serving a second term as director of the San Felipe hospital. He took up his assignments in Washington and Ottawa in 1974.

Dr. Lazarus' survivors include hiswife, Emma C., and a daughter, Tania Roberta, of the home in Bethesda.