Haematological and immunological studies were performed on 36 patients with carcinoma of the endometrium prior to treatment. Haematological and coagulation studies, excluding fibrinogen, showed only minimal abnormality. However, tests for acute phase reactant proteins were abnormal in the majority of patients. There was a reduction in T cells in 31% of patients and a reduction in stimulation with PHA and PWM in 84 and 42% of patients, respectively. Autoantibodies to normal tissue antigens were present in half the patients and immune complexes were increased in 45% of patients. Carcinoembryonic antigen and Β2-microglobulin were increased in 27 and 47% of patients respectively. Although specific tests for endometrial cancer are not yet available, a profile of tests might be of value in the diagnosis and follow-up of patients with the condition.