Species Composition and Age Structure of Rat and Mice (Rodentia: Muridae) in Hlegu Township, Yangon Region, Myanmar was studied during the study period from June, 2016 to February, 2017. A total of six species of rodents, including three species of Bandicota bengalensis, B. indica and B. savilei, two species of Rattus exulans and R. rattus and only one species of Mus cervicolor were observed. In sex ratio, more number of female species was recorded than the male, except in M. cervicolor. Among different species of rats and mice, most of the male and female rats were found to be adults and few were juveniles in this study.

Keywords : Sex Ratio; Rodent Species; Adults; Juveniles.