The Mythopoeic Society is a non-profit group whose aim is to promote high quality fantasy writing and scholarly investigations into fantasy. They were founded in 1967. Since 1971 they have awarded prizes for high quality work in these fields. Beginning in 1992, the fantasy award for fiction was split into an adult category and a children’s category. The award is a statuette of Aslan from C.S. Lewis's Chronicles of Narnia.
Following is a list of the books which have won in the general and the adult fantasy categories. If you are interested in the winners of the children’s category or the scholarly category, you may consult their web site.
Mythopoeic Fantasy Award
Mythopoeic Fantasy Award for Adult Literature
The Mythopoeic Society: http://www.mythsoc.org/mythsoc.html