NEW YORK (AP) _ Fashion designer Georgio Sant'Angelo, who became famous for his body- hugging fabrics and comfortable, elegant clothes, has died of lung cancer. He was 56.

Sant'Angelo, whose ideas have entered the fashion mainstream and are seen in the collections of Calvin Klein, Jean-Paul Galtier and Donna Karan, died Tuesday at St. Luke's-Roosevelt Hospital Center in Manhattan.

''He was a highly original and imaginative designer,'' said Bill Blass. ''He brought a lot of energy and ability to American fashions.''

Sant'Angelo became a fashion designer by chance. In 1967, while working as a textile designer, he took some pieces of plastic home one evening and fashioned them into geometric shaped jewelry.

The jewelry caught the eye of Diana Vreeland, then editor of Vogue, who published pictures of the work.

Sant'Angelo won a Coty Award for the designs the following year. He soon translated his ideas from plastic to tie-dyed fabrics, and entered the fashion business.

Born Count Giorgio di Sant'Angelo in Florence, Italy, he grew up on his grandfather's farm in Argentina.

He attended the Institute of Industrial Design in Barcelona and studied at the Sorbonne in Paris before coming to the United States in the 1960's to work for the Walt Disney Studies in California.

He is survived by a brother, Hector Imperatrice of Rosario, Argentina.