A 5 year-old girl presented with typical features of isosexual precocity with breast and pubic hair development (Tanner stage 3) and menarche, following a few months history of hirsutism of the back and thighs. Stimulation testing revealed GnRH-independent precocious puberty, tertiary hypothyroidism, hyperprolactinemia and mild testosteronemia. The ovaries in ultrasound examination were prepubertal. Tumor markers beta-hCG and AFP were markedly elevated and a 2.5 x 1.5 cm suprasellar germ cell tumor (GCT) was visualized by MRI. Combined chemotherapy followed by radiotherapy resulted in normalization of pubertal features along with estrogen and marker levels. Our observations support the possibility of hCG-dependent precocious puberty (PP) in girls caused by suprasellar hCG-secreting tumor. We emphasize the need of diagnostic management of hCG-dependent PP not only in boys, but also in girls, especially when they present even slight features of androgenization. We hypothesize that the rarity of isosexual PP in girls with hCG-secreting suprasellar GCT results not only from the lower occurrence of these tumors in girls than in boys, but above all from a rare simultaneous concomitant incidence of both high tumor aromatase activity and hCG secreting potency.