Objective : To demonstrate an objective method of measuring lip symmetry after cleft lip repair by comparing patients with unilateral cleft lip (UCL) to non-cleft lip controls using the SymNose computer program. Design : Retrospective cohort study comparing several parameters of lip symmetry between UCL cases and controls. Participants were represented by digital photographs that were traced using SymNose. Setting : This study was performed at the South West Cleft Unit, Bristol, U.K. Participants : Forty-four participants aged 10years (±1year) were recruited into and completed the study. A consecutive case series of 22 patients with UCL ± palate had previously undergone primary repair. Twenty-two age-matched controls were recruited from a local primary school. Main Outcome Measures : Lip symmetry, expressed as the percentage mismatch of an overlaying of the left upper lip area and upper vermillion border area over the right, horizontal lip tilt, and lateral deviation of the lips. Results : A significant increase in labial asymmetry was seen in the UCL group in the following parameters: upper lip mismatch and upper vermillion border mismatch. No significant differences were observed in horizontal lip tilt or lateral lip deviation. Conclusion : This study supports the use of SymNose for the objective quantitative assessment of lip symmetry as an outcome measure of surgery following cleft lip repair. It allows comparison of surgical techniques and can be used to perform audits. It is a time-efficient process, relatively inexpensive, and straightforward to use.