A series of 427 patients with congenital dacryostenosis involving 572 eyes was seen at the Children's Hospital of Philadelphia. All patients were treated conservatively with antibiotics and massage prior to decision by the parents to request probing. Congenital dacryostenosis, as well as resolution of symptoms, were confirmed by clinical examination and use of a modified dye disappearance test. In 572 eyes, the success rate of initial probing was found to be 97% under 13 months of age. Over 13 months, however, the mean success rate was found to be 54.7%. When broken down into smaller age categories, a stepwise progression was observed from 76.4% between 13 and 18 months to 33.3% for patients probed after 24 months. In addition, the number and complexity of subsequent procedures appeared to increase along with the age at which the initial probing was performed. These data suggest that initial probing should be done prior to 13 months of age depending on the severity of symptoms and parent compliance with medical management.