This study aimed to investigate the most prevalent stage in each age-group of children with congenital cholesteatoma (CC) and verify the correlation between the stage and the age of the patients for the type of CC ("closed" keratotic cyst and "open" infiltrative types). Patients diagnosed with CC between 2004 and 2009 (n = 156; 116 boys and 40 girls; mean age, 5 years and 5 months; range, 12 months-16 years and 7 months) were enrolled retrospectively. Assessment of stage and type of CC was performed with preoperative high-resolution temporal bone computed tomography and intraoperative findings. The stage of CC was determined using Potsic's staging system classified into four stages according to ossicular involvement and mastoid extension. The patients consisted of groups divided on the basis of a 2-year interval. The prevalence of stage I began to decline from the age-group of 1-2 years. In contrast, the prevalence of stages III increased from the age-group of 3-4 years and that of stage IV from the age-group 5-6 years. The prevalence of "open" infiltrative type CC increased from approximately the age of 7 years, thus showing some correlation with age but not with stage. The prevalence of CC with the advanced stage increased since the age of 2 years. Therefore, the importance of early diagnosis and treatment of CC should be more emphasized.