This study aims to determine the weed species that exist on Zea mays L. plant in paddy fields Padang Galak village, East Denpasar, Bali Province. This study is useful to provide information about the species of weeds found in maize (Zea mays L.) in the fields of biology and agriculture, so weed control on Zea mays L. Plant can be implemented. Research was conducted from January 7 until March 11, 2011. In this study used the method of cruising (exsploration sampling). To be more efficient and systematic results, also used a systematic method of lines. The results found 36 weed species belonging to 20 families. The distribution of the weed species, was found in Zea mays L. plant age of 4 weeks, which composed of 8 families 16 Species. Weeds found in Zea mays L. plants aged of 6 weeks (the formation of fruit) consisted of 10 familes and 23 species. While weeds found in Zea mays L. plants 8 weeks of age (ripening fruit) were 14 families and 28 species. Weeds found in Zea mays L. plants aged 10 weeks (before harvest) comprised of 20 families and 36 species.