11alpha-Hydroxypoststerone (1) and herkesterone (2), two new natural ecdysteroids, were isolated from the herb Serratula wolffii. The former compound is the first 11-hydroxylated C21 ecdysteroid, while the latter is a new ecdysteroid with a 7,9(11)-dien-6-one chromophore. Their structures were determined using a combination of spectroscopic techniques.