This prospective study investigated the prevalence, the ocular features and the impact on zootechnic performance of congenital entropion in a sheep flock. A total of 318 Ile de France and Texel purebred and crossbred lambs were observed from birth to the age of 14 days. Repeated ocular examinations were performed and clinical signs were scored at different time points with a three-point severity scale. Spontaneous evolution of ocular clinical signs presented by entropic eyes was then monitored on a weekly basis from the age of 14 days until complete recovery occurred. The impact of entropion on growth was evaluated by measuring the bodyweight and by comparing affected animals with a breed-, gender- and litter size-matched-control group. Fifty-two lambs were affected by entropion. There were no gender-related differences, but significant differences among litter size and breed: triplet lambs, Ile de France and crossbred lambs were significantly more affected by entropion than purebred Texel lambs. The median time after which eyes with entropion recovered spontaneously was 7 days (range 2-42 days). No significant differences were found between groups regarding average daily gain. In conclusion, traits such as litter size and breed did influence the occurrence of congenital entropion in lambs. Moreover, this condition did not impact on lamb growth and resolved spontaneously.