Background/aims The literature on the prevalence and demographics of congenital nasolacrimal duct obstruction (CNLDO) is 30–70 years old and largely comprises small sample sizes. This study provides epidemiological findings of this common disorder from the largest cohort reported to date.

Methods The medical records of all children (<5 years of age) residing in Olmsted County, Minnesota, when diagnosed with CNLDO from 1 January 1995 through 31 December 2004, were reviewed.

Results Of 17 713 newborns born during the 10-year study period, 1998 were diagnosed with CNLDO, yielding a birth prevalence of one in nine live births. The diagnosis was made in approximately 90% by a primary care physician, at a median age of 5 weeks, with no gender predilection. Compared with the reference population, CNLDO was associated with premature birth (p=0.005) and was more prevalent among Caucasians (p<0.001). Two-thirds of patients initially presented with discharge alone, 18% with tearing alone and 15% with both discharge and tearing.

Conclusions In this large population-based cohort, CNLDO occurred in one in nine live births with no gender predilection. Prematurity and Caucasian race were associated with the development of CNLDO. Mucopurulent discharge was a much more common feature than tearing at initial presentation.