We have constructed deletion maps of chromosome 3p for cancers of the female genital tract (uterine endometrium, uterine cervix and ovary). The tumours were tested for loss of heterozygosity using CA-repeat polymorphisms. The high degree of informativeness of these markers allowed the construction of detailed deletion maps from a relatively small number of samples. A common region of deletion was identified at chromosome 3p13-21.1 in endometrial cancer and at 3p13-14.3 in cervical cancer; 5 out of 13 (38%) endometrial cancers and six out of eight (75%) cervical cancers showed loss of heterozygosity at these regions. In ovarian cancer a separate common region of deletion was identified at 3p21.1-22; two out of four (50%) ovarian cancers had alleles deleted at this region. These data suggest the presence of a tumour-suppressor gene(s) for endometrial and cervical cancer at 3p13-21.3 and a separate gene at 3p21.1-22 that is involved in the carcinogenesis of ovarian cancer.