Testicular neoplasms are uncommon tumors of childhood. These tumors comprise the germ cell tumors, and other tumors that may originate from histological testicular components, which are unrelated to the germinal lineage. Among the latter are the sex cord-stromal tumors (SCST), an important entity in newborns. SCSTs comprise, among others, granulosa cell tumors, which are more common in the ovary, but in rare cases may develop in the testis. The prognosis is excellent since it is universally benign. Diagnosis, which is sometimes challenging, is usually made after orchiectomy and pathological examination, which is characterized by morphological features and positive expression of inhibin, calretinin, and vimentin, and negative for alpha-fetoprotein. The authors present the case of a newborn with a right enlarged testis detected during the first examination after birth. Ultrasonography showed a heterogeneous solid/cystic mass in the right testis, without retroperitoneal lymphadenopathy. A right inguinal orchiectomy was performed 21 hours after birth. Pathologic examination revealed a juvenile granulosa cell tumor of the right testicle. After 4 years of follow-up, as expected, the child presented an uneventful outcome.