The clinical implications of the epidermal growth factor (EGF) and its receptor (EGF-R) were studied in 52 squamous cell carcinomas of the uterine cervix. In comparison to 40 biopsies of the normal cervix EGF-R capacity was significantly increased in the carcinomas, while the affinity was unchanged. The amount of EGF-like substances extracted from the tumors was increased in patients with lymph node metastases, in whom 5-year survival is reduced. Irrespective of tumor stage patients with a very high level of EGF-R (greater than 100 fmole/mg protein) were more likely to have recurrences later or to die from disease: recurrence or death occurred in 5 of 7 patients with high capacity and in 2 of 45 patients with low capacity. Our data suggest that the level of EGF-R is indicative of the biological aggressiveness of cervical carcinomas.