To clarify the role of GATA transcription factors in ovarian carcinogenesis, we analyzed the expression and methylation states of GATA-4/-5/-6 in eight human ovarian cancer cell lines. GATA-4/-5 were methylated in three and two cell lines without their expression, respectively. Methylation of GATA-4/-5 was also detected in nine and five of 15 primary ovarian cancers, respectively. GATA-6 was not methylated in any cases. We transiently over-expressed GATA-5 in the JHOC-5 cell line using an adenovirus system, resulting in that apoptosis was induced and apoptosis-related genes, such as Apaf-1, were up-regulated. These data suggest that GATA-4/-5 may be involved in ovarian carcinogenesis.