A consecutive series of 1530 patients with carcinoma of the breast has been reviewed to study the influence of age and marital status on the disease.The risk of developing breast cancer increases with age, though a peak may be reached at 75 years. The risk of developing a tumour of advanced clinical stage at presentation apparently increases with age. Local recurrence rates and mortality rates are similar at all ages. It is concluded that the therapy required is similar in all age groups.The increased risk of developing breast cancer in "never married" women is in the postmenopausal period. Survival rates and the distribution of the various presenting clinical stages are similar in both single and married patients.Though ageing and marital status have an initiating effect on breast cancer, they do not have a continuing effect on the established disease.