The cost of disease within the dairy industry is associated with loss of yield, discarded milk, cost of treatment and reduced fertility. Mastitis and lameness are two of the most financially important health problems associated with dairy production in the UK. Mastitis alone is estimated to account for approximately 10% of all cull cows and to have an associated cost of £218 per case (Kossaibati and Esslemont, 1995). Lameness accounts for approximately 6% of cull cows and has an associated cost of £273 per case (Kossaibati and Esslemont, 1995). In the present study somatic cell count (SCC) and locomotion score (LS) records were used as indicators to estimate the influence of genetic merit for milk production on mastitis and lameness.