Katherine Paterson's novel "Jacob Have I Loved" and Arnold Lobel's "Fables" have won the John Newbery and Randolph Caldecott medals respectively, two of the most prestigious awards in children's literature.

The Newbery Medal has been given annually since 1921 to the most distinguished children's book of the year. It honors John Newbery, an 18th-century publisher and seller of children's books. The Caldecott Medal, first awarded in 1938, honors the most distinguished picture book of the preceding year.

The winners will be announced this morning at the Sheraton-Washington Hotel by the American Library Association, which is having its mid-winter meeting in Washington this week.

Paterson, 48, won the Newbery Medal in 1978 for her novel, "Bridge to Terabithia," and has also won two National Book Awards for "The Master Puppeteer" and "The Great Gilly Hopkins," both novels. "Jacob Have I Loved" (Crowell) is the story of "Wheeze" Bradshaw, an independent, tomboy growing up with her more accomplished and prettier twin sister on a small island in the Chesapeake Bay.

Paterson, a former resident of Takoma Park who now lives in Norfolk, Va., said yesterday, "I'm in a state of shock" on hearing of the award.

Lobel, 47, is a prolific and popular illustrator and writer living in Brooklyn. Probably best known for his "Frog and Toad" books, he has won both Caldecott and Newbery Honor awards. "Fables" (Harper & Row) consists of 20 witty original moral tales accompanied by colorful animal portraits.

This year's Newbery Honor Books -- the runners-up in the competition -- are Madeleine L'Engle's novel "A Ring of Endless Light" (Farrar, Straus & Giroux) and Jane Langton's fantasy "The Fledgling" (Harper & Row). The four Caldecott Honor Books are: "Mice Twice," by Joseph Low (Atheneum); "Truck," by Donald Crews (Greenwillow); "The Bremen-Town Musicians," by Ilse Plume (Doubleday); and "The Gray Lady and the Strawberry Snatcher," by Molly Bang (Four Winds).

Although no money is awarded with the prize, the winners are virtually guaranteed a large sale for their books, which are likely to remain in print indefinitely.