NOT 100% natural fiber. body: 59% cotton, 38% nylon, 3% spandex. yoke, ruffles, & pockets: 95% cotton, 5% spandex. -----Matilda Jane, Children's 6 yrs, 59% cotton/38% nylon/3%spandex, brown  & teal ("Ethel") sleeveless blouse. Good used condition