Sera of 120 patients with cervical cancer were screened for cold reacting, complement dependant autolympho-cytotoxins (CoCoCy). These antibodies occurred in 21,7% of the patients in comparison with 11,2% of 116 controls. The highest percentage of CoCoCy-antibodies was detected in the sera of patients with cervical cancer stage I (27,6%). Thus demonstration of CoCoCy-antibodies may be of pathogenetic rather than of diagnostic interest. CoCoCy-antibodies could be seen to reflect autoimmune reactions in cervical cancer.