FAM64A is a mitotic regulator which promotes cell metaphase-anaphase transition and is highly expressed in a cell-cycle-dependent manner. In this study, we examined the clinicopathological and prognostic significance of FAM64A mRNA expression in gynecological cancers. We conducted a bioinformatics analysis of FAM64A mRNA expression using Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), xiantao, The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN), and Kaplan-Meier (KM) plotter databases. FAM64A expression was elevated in breast, cervical, endometrial, and ovarian cancers when compared with normal tissue. Expression was positively correlated with white race, low T stages, infiltrating ductal carcinoma, or favourable PAM50 classification in breast cancer patients, and with clinical stage, histological grade and TP53 mutation, and endometrial cancer serous subtype. FAM64A expression was negatively associated with overall and/or recurrence-free survival rates in breast and endometrial cancer patients, while the opposite was observed in cervical and ovarian cancer patients. FAM64A functioned as an independent predictor of overall and disease-specific survival in breast cancer patients. FAM64A-correlated genes were involved in ligand-receptor interactions, and chromosomal, cell cycle, and DNA replication processes in breast, cervical, endometrial and ovarian cancers. Top hub genes primarily included cell cycle-related proteins in breast cancer, mucins and acetylgalactosaminyl transferases in cervical cancer, kinesin family members in endometrial cancer, and synovial sarcoma X and the cancer/testis antigen in ovarian cancer. FAM64A mRNA expression was positively related to Th2 cell infiltration, but negatively associated with neutrophil and Th17 cell infiltration in breast, cervical, endometrial, and ovarian cancers. FAM64A expression may be considered a potential biomarker reflecting carcinogenesis, histogenesis, aggressive behaviour, and prognosis in gynecological cancers. Impact statement What is already known on this subject? FAM64A is located in cell nucleolar and nucleoplasmic regions, and during mitosis it putatively controls metaphase-to-anaphase transition. FAM64A appears to regulate different physiological processes, including apoptosis, tumorigenesis, neural differentiation, stress responses, and the cell cycle. What the results of this study add? FAM64A expression was up-regulated in breast, cervical, endometrial, and ovarian cancers, and positively correlated with white race, low T stages, infiltrating ductal carcinoma, or favourable PAM50 classification in breast cancer patients, and with clinical stage, histological grade, and TP53 mutation, and a serous subtype in endometrial cancer. FAM64A expression was negatively associated with overall and/or recurrence-free survival rates in breast and endometrial cancer patients, while the opposite was observed in cervical and ovarian cancer patients. FAM64A functioned as an independent predictor of overall and disease-specific survival in breast cancer. FAM64A-correlated genes were involved in ligand-receptor interactions, chromosomal, cell cycle, and DNA replication processes, while FAM64A mRNA expression was positively related to Th2 cell infiltration but negatively correlated with neutrophil and Th17 cell infiltration in four gynecological cancers. What the implications of these findings for clinical practice and/or further research? In the future, abnormal FAM64A mRNA expression may serve as a biomarker of carcinogenesis, histogenesis, aggressiveness, and prognosis in gynecological malignancies.