Granulosa cell juvenile tumours, defined in 1976 by Scully as a separate unit are found mostly in girls during the first two decades of life. On inspection under an optic microscope they are characterized by the presence of non-differentiated "blastemoid" structures and the formation of solid follicular formations and cysts. In our first case we observed a bilateral juvenile tumour made up of granulosa cells in a 8-month-old girl where the tumour produced symptoms of pseudopubertas praecox isosexualis. In the second case in a 9-month-old girl also with symptoms of pseudopubertas praecox isosexualis the authors detected in the left ovary a tumour which probably is a less differentiated variety of the juvenile granulosa cell tumour. These tumours belong into the group of little differentiated gonadal-stromal tumours with ICD-O code M-8590/1.