This study investigated the relationships between a mindfulness-based stress reduction meditation programme for early-stage breast and prostate cancer patients and quality of life, mood states, stress symptoms and levels of cortisol, dehydroepiandrosterone-sulphate (DHEAS) and melatonin. A total of 59 patients with breast cancer and 10 with prostate cancer enrolled in an 8-week mindfulness-based stress reduction (MBSR) programme that incorporated relaxation, meditation, gentle yoga and daily home practice. Demographic and health behaviour variables, quality of life, mood, stress and the hormone measures of salivary cortisol (assessed three times per day), plasma DHEAS and salivary melatonin were assessed pre- and post-intervention. Significant improvements were seen in overall quality of life, symptoms of stress and sleep quality, but these improvements were not significantly correlated with the degree of programme attendance or minutes of home practice. No significant improvements were seen in mood disturbance. Improvements in quality of life were associated with decreases in afternoon cortisol levels, but not with morning or evening levels.