Incontinentia pigmenti(Bloch-Sulzberger syndrome) is a sex-linked hereditary disorder so girls are almost exclusively affected. The frequency rate is approximately 1:40,000 among girls. It is associated with skin, ocular, dental, skeletal and central nervous deformities. We reported 2 cases of medically diagnosed IP patients who were 4 and 5 years old girls. They had thin and sparse hair, and represented congenital missing of multiple primary and permanent teeth, accessory cusps and cone-shaped crowns. Therefore we report the dental manifestations and treatment progress.