The term hock lesion describes incidences of hair loss, thickened skin, wounds, scabs, and swellings occurring over the tarsal joint. Hock lesions in dairy cattle are a widespread problem around the world. In the UK, a recent study found approximately 99% of examined cows had at least some callused area over a hock (Haskell et al., 2006). The presence of hock lesions is correlated with injuries of the teat, carpal joints and skin, as well as increases in mobility score, high somatic cell counts, a greater incidence of clinical mastitis, and higher culling and annual death rates. Differences in the prevalence and severity of hock lesions according to the lying surface and cubicle design have been identified. Cow-related factors and management variables have also been postulated as possible risk factors. Recognition of the condition and practical solutions aimed at resolving it have however, been limited. The aim of this study was to determine the prevalence of hock lesions in lactating cattle on dairy farms in the East Midlands of the UK, and the significance of potential risk factors in the development of the lesions.