Blood samples were collected from unstressed cattle and from cattle undergoing handling stress, transport stress and slaughter. The blood was analysed for ACTH, cortisol, thyroxine stimulating hormone, tri-iodothyronine (T3) and catecholamine concentrations, and for haematocrit, total plasma protein, plasma lipid, lactate and glucose concentrations. Compared to control values handling significantly increased T3, cortisol, lipid and lactate concentrations. Compared to handling, transport stress was associated with increased catecholamines and lactate concentrations, a decreased cortisol concentration and similar concentrations of T3, lipid and glucose. Compared to transport, slaughter resulted in high catecholamines, lactate and glucose, and low T3, cortisol and lipid levels. It is concluded that the response to stress has two phases, a hypothalamic-adrenal cortex phase which is associated with perceived environmental stress such as noise, and a sympathetic-adrenal-medulla phase which is associated with neurogenic stress such as transport or specifically the massive sympathetic discharge caused by stunning. Combinations of stresses produce a mixed response.