BACKGROUND: Infants with congenital tracheal stenosis may also have unilateral lung agenesis or severe lung hypoplasia. The purpose of this review is to evaluate our results with these patients and compare their presentations and outcomes to those of tracheal stenosis patients with two lungs. METHODS: Our database was queried for patients undergoing tracheal stenosis repair since 1982. Patients were divided into two groups based on pulmonary anatomy of single lung (SL = unilateral lung agenesis or severe hypoplasia) or two lungs (BL = bilateral lungs) and analyzed to compare presentation and outcomes. RESULTS: From 1982 to 2008, 71 patients had tracheal stenosis repair. Bilateral lungs were present in 60 patients; 9 patients had an absent (4) or severely hypoplastic (5) right lung, and 2 patients had an absent left lung (SL = 11). Age at repair was similar between groups; median age 0.42 years in the SL group (mean 0.80 +/- 1.0 years) versus 0.37 years in the BL group (mean 0.91 +/- 2.1 years, p = not significant [ns]). In the SL group 8 of 11 (73%) were intubated preoperatively versus 15 of 60 (25%) in the BL group (p = 0.004). In the SL group 4 of 11 (36%) patients had pulmonary artery sling versus 20 of 60 (33%) of BL patients (p = ns). In the SL group 2 of 11 (18%) versus 14 of 60 (23%) in the BL group had intracardiac anomalies requiring simultaneous repair (p = ns). Procedures included pericardial tracheoplasty (2 vs 26), tracheal autograft (4 vs 16), slide tracheoplasty (3 vs 8), and tracheal resection (2 vs 10). Overall mortality (operative and late) was 2 of 11 (18%) SL versus 10 of 60 (17%) BL (p = ns). Median postoperative length of stay was 43 days SL (mean 48.6 +/- 40) versus 30 days BL (mean 52.2 +/- 65) (p = ns). The incidence of postoperative tracheostomy (SL group) was 0 of 3 for slide tracheoplasty and 5 of 8 for the other techniques (p = 0.12). CONCLUSIONS: Despite the increased severity of pathology and increased critical presentation of tracheal stenosis patients with unilateral lung agenesis or severe hypoplasia, outcome measures of mortality and length of stay were similar to patients with two lungs. The incidence of associated pulmonary artery sling (1 of 3) and intracardiac anomalies (1 of 4) was similar. Unilateral lung agenesis or severe hypoplasia should not preclude operative repair of tracheal stenosis. Slide tracheoplasty is our current procedure of choice for these infants.