Sheep lameness is a major welfare concern as well as a challenge for sheep farmers because it is associated with reduced production and economic losses. The etiology of lameness can be either of environmental origin associated with housing, nutritional and genetic factors, or associated with the physiological changes during the productive life of sheep. Although, there is now a large body of research studies about lameness in meat producing sheep, such information in the literature regarding dairy sheep is very limited (Grogono-Thomas and Johnston, 1997; Winter, 2004). The Greek sheep industry is mainly based on milk production and is characterised by the recent establishment of many large, commercially run flocks. The aims of this study were to determine the prevalence of lameness (total number of cases at a given time) in such flocks of Chios sheep and to obtain data concerning the risk factors and type of management in relation to lameness.