Menkes disease (MD, MIM 309400) is a fatal X-linked recessive disorder that is caused by mutations in the gene encoding ATP7A, a copper-transporting, P-type ATPase. Patients with MD are characterized by progressive hypotonia, seizures, failure to thrive, and death in early childhood. Two Korean patients were diagnosed with Menkes disease by clinical and biochemical findings. We found one missense mutation and one gross deletion in the ATP7A gene in the patients. The missense mutation in Patient 1, c.3943G>A (p.G1315R) in exon 20, was identified in a previous report. Patient 2 had a gross deletion of c.1544-?_2916+?, which was a novel mutation. The patients’ mothers were shown to be carriers of the respective mutations. Prenatal DNA diagnosis in the family of Patient 2 was successfully performed, showing a male fetus with the wild-type genotype. The gross deletion is the first mutation to be identified in the ATP7A gene in Korean MD patients. We expect that our findings will be helpful in understanding the wide range of genetic variation in ATP7A in Korean MD patients.