Craniosynostosis is a congenital anomaly in which cranial sutures close prematurely and restrict skull growth. In this paper, the case of two siblings, a male and a female, who were both diagnosed as craniosynostosis is reported. They underwent corrective osteotomy for cranial vault remodeling. A 22-month-old female infant who was brought to the department of plastic and reconstructive surgery of the authors' hospital was diagnosed with plagiocephaly. At the same time, her 7-month-old brother was diagnosed with brachycephaly. In the case of the female infant, corrective coronal osteotomy and supraorbital bar advancement were performed. Her brother underwent frontal advancement osteotomy using Tessier's tongue in the groove procedure. After the correction of the craniosynostosis, the two patients recovered in several days later, and the results were good in both cases cosmetically and functionally. They showed normal head circumference increasing curves and no symptom of functional disorder in their last follow-up. Isolated or nonsyndromic craniosynostosis is sporadic but mostly autosomal dominant. This paper presents a case of craniosynostosis with a genetic tendency; and although it occurred between siblings, the affected lesions differed. Thus, appropriate diagnosis and management in patients are needed.