BACKGROUND Aggressive malignant primary orbital tumors are extremely rare in newborns. The current cases further clarify the clinical features of malignant primary orbital tumors in neonates. CASE SUMMARY At the time of presentation at the Seventh Center of People's Liberation Army General (PLAG) Hospital, the children were 1-, 2- and 5-mo-old, respectively, and included 2 boys and 1 girl. All three cases had unilateral proptosis at birth, and underwent mass excision and histopathologic examination. A peripheral primary neuroectodermal tumor, an aggressive infantile fibromatosis and an embryonic rhabdomyosarcoma were diagnosed, respectively. The first case underwent routine chemotherapy following surgery but died within three months due to worsening condition as the tumor spread throughout the body. The other two children were treated by surgery, and at the follow-up visits 6 mo and 1 year after surgery, respectively, the wound was completed healed, and they had normal growth and development without radiotherapy or chemotherapy. A review of highly uncommon orbital tumors in newborns is also provided. CONCLUSION Malignant primary tumors should be considered in the presence of unilateral proptosis in newborns.