Modern surgical techniques allow congenital cataract surgery to be performed much more successfully. The development of a secondary glaucoma is the most dreaded postoperative complication (one third of all pediatric secondary glaucomas). Due to the limited value of the available literature, data on prevalence are unreliable. A 10-year postoperative incidence of 10-25% is given in the literature for developing secondary glaucoma and the frequency increases with the duration of follow-up. A major risk factor seems to be the age at the time of surgery. The younger the patient is at the time of surgery the higher the risk of secondary glaucoma. A microcornea seems to be another risk factor in multivariate analysis. The following postoperative changes might be involved in the pathogenesis: peripheral anterior synechia, high iris insertion and membranous material over the trabecular meshwork. Additionally postoperative inflammation, reaction to lens epithelial cells, perioperative barotrauma and loss of anterior segment architecture might also be responsible. In order to evaluate the optimal age window for congenital cataract surgery and risk factors for the development of secondary glaucoma, a prospective longitudinal study is mandatory.