Cyclic neutropenia is a rare haematologic disorder. This case report presents a 6-year-old girl who was referred in order to treat gingival recession, and was finally diagnosed as having cyclic neutropenia based on an oral examination, complete blood counts and a sternal puncture bone marrow test. The patient received systematic granulocyte colony-stimulating factor therapy, full-mouth scaling and root planing and was followed up for 4 years. Due to irregular periodontal maintenance and poor oral hygiene, severe gingival inflammation and deep pockets persisted in the permanent dentition of the patient. Keywords: cyclic neutropenia, periodontitis, oral hygiene, periodontal initial therapy