Congenital neutropenia (CN) is a rare disorder, and the most common gene responsible for CN is ELANE. Furthermore, the mutations of HAX1, G6PC3, and JAGN1 genes may cause CN. These patients generally find great benefit from subcutaneous administration of Granulocyte Colony Stimulating Factor (GCSF). In recent years, Biallelic Colony Stimulating Factor 3 Receptor (CSF3R) mutations have been described as an underlying defect of CN in several children. In contrast to the previous group, the patients who have a CSF3R mutation do not respond to GCSF treatment. Here, we present a CN patient with hypomorphic biallelic CSF3R mutation responding to GCSF.