The occurrence of a second primary cancer in a cancer survivor is well documented. It may be synchronous or metachronous. Incidence of metachronous cancer involving cervix is 0.82% to 1.33%. One such metachronous cancer is that of breast and cervix. We present a case of a woman who received tamoxifen for invasive ductal cancer of breast following a modified radical mastectomy and subsequently developed adenocarcinoma of cervix after six month of tamoxifen therapy. The role of tamoxifen in pathogenesis of cervical cancer and that of human papillomavirus infection in pathogenesis of both cancer of cervix and breast cancer has been well recognized. In our patient, the adenocarcinoma of cervix (rare occurrence) which is likely due to six month of tamoxifen therapy is a perplexing question. Women diagnosed and treated for breast cancer need to be followed up for development of other metachronous gynecological cancers.