Aim: To report full dental treatment of 7-year-old fraternal twin girls diagnosed with cyclic neutropenia. Background: Cyclic neutropenia is a rare autosomal-dominant disorder characterized by neutropenia that recurs every 14–35 days. It is estimated that the incidence of cyclic neutropenia is one to two per million. Clinically, it manifested by repetitive episodes of fever, susceptibility to infection, pharyngitis, recurrent mouth ulcerations, and periodontal diseases. Medical management includes supportive treatment, antibiotic therapy for infectious diseases, and granulocyte colony-stimulating factor (G-CSF), to raise blood neutrophils. Dental management of cyclic neutropenia patients varies from thorough oral hygiene, regular dental follow-ups, and surgical or nonsurgical periodontal treatment. Case description: Seven-year-old fraternal twin girls diagnosed with cyclic neutropenia at the age of 6 months. They were referred from their pediatric hematologist after complaining of recurrent aphthous ulcer and extensive dental caries. Dental treatment started with preventive and supportive treatment and then full dental treatment under general anesthesia and maintenance visits for 6 months. Conclusion: This report emphasizes the importance of dental treatment for patients with compromised medical conditions. Clinical significance: The oral cavity is a potential source of inflammation or infection, and treating oral diseases could prevent serious systemic diseases.