Locomotion scoring systems are procedures used to evaluate the quality of cows’ locomotion. Locomotion scoring systems are mostly used to classify cows as lame or non-lame. Since lameness is considered an important problem in modern dairy farming, the objective of this thesis was to evaluate the performance of raters to assess locomotion in dairy cattle. In different experiments raters showed a large variation in reliability and agreement values when assessing locomotion. The factor affecting reliability and agreement most is the rater him/herself. Given the large variation in reliability and agreement, it can be concluded that raters have a moderate performance to assess consistently locomotion in dairy cows. The variable performance of raters when assessing locomotion limits the practical utility of locomotion scoring systems as part of animal welfare assessment protocols or as golden standard for automatic locomotion scoring systems.