Proteus syndrome is a complex disorder comprising malformations and overgrowth of multiple tissues and characterized by its polymorphism and mosaicism. The syndrome is rare and sporadic. Oliveira M da C et al reported the first case of Proteus syndrome associated with precocious puberty in a boy. We are reporting a case of a 7-month old girl with Proteus syndrome who developed a juvenile granulosa cell tumor in one ovary causing precocious puberty. At our knowledge this is the first case of Proteus syndrome with precocious puberty in a female.