We have examined 35 human tumors of the uterine cervix (carcinoma presenting the highest incidence in Mexico; about 34% of women's malignant tumors) for alterations of the cellular myc (c-myc) protooncogene. Elevated amplification and/or rearrangement of the c-myc oncogene were detected in most (approximately 90%) samples (48% showed amplification and 43% presented both alterations). Most tumors were stage II cervical carcinomas and for some of them we detected up to 60-fold amplification of c-myc. These results suggest an important role for c-myc oncogene in the development of tumors of the uterine cervix.