The assessment of weed flora was conducted at two zones of southern Oromia in the 2020-2022 production years. From each zone the districts were purposely selected based on the of crops cultivated. Identification of the major crop weeds that cause production losses is essential for collecting information about the weeds as well as for developing the necessary management measures. On the other hand, wrong identification of the target weed species in the native habitat may lead to the introduction of the wrong management options, which may also fail to reduce weed interference. The results showed a total of 19 weed species from 8 families in common bean, 21 species from 8 families in maize, and 21 species from seven families were identified in Teff fields. Weed families identified from the surveyed areas include Asteraceae, Commelinaceae, Cyperaceae, Fabaceae, Papaveraceae, Amaranthaceae, Poaceae and Solanaceae. Among the identified weed species, Asteraceae and Poaceae were the most dominant plant families. Consequently, weed species composition varied among districts, therefore different weed management options would be required for the districts that differ in weed flora composition. However, in some districts there were similar indices, in those districts the applied management options should be analogous.

Keywords: weed abundance, weed flora, weed frequency, rotational crops, similarity index