Luba Jaffe, 56, an actress, journalist and translator who had lived here since 1956, died of cancer Monday r Georgetown University Hospital.

Mrs. Jaffe was born in Russia and reared in Brazil where she was an actress and journalist. As a journalist, she interviewed former Brazilian president Juscelino Jubitschek.

She first came to this country in 1950, under a grant of the Brazilian Ministry of Education, to study at the University of California at Los Angeles. Two years later she traveled to Israel as a memeber of the staff of the Brazilian legation.

After working as a translator for the Indian Embassy in Brazil, she came to Washington in 1956 and worked for the Indian Embassy here and then for the Brazilian Air Force's purchasing commission.

In recent years she had translated the works of Elie Wiesel from English and French editions into Portuguese. Her translation of Wiesel's "Souls on Fire" is to be published in Brazil later this year.

She also had worked as a real estate agent for Snider Brothers and Boss & Phelps Realtors in Washington from about 1970 to 1975.

Mrs. Jaffe was a member of Hadassah.

Survivors include her husband of 22 years, Sidney A., of the home in Bethesda; a daughter, Debby, of Ithaca, N.Y., and her mother, Ester Vatinic, and a sister, Lucia Aizim, of Rio de Janeiro.

The family suggests that expressions of sympathy be in the form of contributions to the Georgetown Univesity Medical Center.