Abstract: The Arabidopsis MALE STERILITY2 (MS2) gene is required for anther and pollen development; sequence analysis indicated that the OsMS2 (Os03g07140) gene shares high similarity with MS2 in Arabidopsis. Here, we describe the functional analysis of OsMS2 in rice anther development by the RNA interference approach. Transgenic lines with the introduced gene expressing double-stranded RNA with the OsMS2 DNA fragment grew normally during their vegetative phase but displayed reduced male fertility. The reduced fertility phenotypes were as sociatedwith down-regulated OsMS2 transcript levelmediated by RNAi. Further cytological observations of the anthers of transgenic lines showed that knock-down of OsMS2 led to delayed tapetumdegeneration and abnormal microspores in the anther. Scanning electron microscopy revealed that the microspores could not form normal exine. Thus, OsMS2 is an AtMS2 homologue and plays an important role in rice anther development.