A new case of precocious puberty secondary to production of human chorionic gonadotropin (HCG) by an hepatoblastoma was studied in an 8-month-old infant. A review was made of the 35 cases of paraneoplasic precocious puberty previously reported in the literature. The most frequent cause is hepatoblastoma, which was responsible for 18 cases. There are nine reports of mediastinal teratoma, six of which were observed in patients with Klinefelter Syndrome. In another six cases, the paraneoplasic syndrome was attributed to intracranial tumoration, and two of these patients showed teratoma with areas of choriocarcinoma, whereas germinoma was suspected for clinical reasons in another three. Lastly, one case of presacral teratoma and one of retroperitoneal carcinoma were reported. The differential characteristics of paraneoplasic precocious puberty are: almost exclusive occurrence in males, because of tumoral production of HCG, moderate or absent increase of testicle size, hyperplasia of Leydig's cells without spermatogenesis, and rapidly progressive signs of puberty.