Parthenium hysterophorus is an invasive alien species that is believed to have been introduced tornEthiopia during the1970s along with the grain aid donated by USA, and for the same reason inrnthe 1980â€™s in the study area. In this study the biological and socio-economic impact of P.rnhysterophorus were assessed in Kobo (North Wello, Ethiopia) to develop up-to-date informationrnfor future prevention and control mechanisms. The biological impacts of P. hysterophorus wererninvestigated using cover, comparison and soil analysis techniques. The socio-economic impactsrndue to P. hysterophorus was studied by interviewing a total of 114 sample farmers that werernselected randomly from the list of farmers in the study area, that is 38 farmers from each stratumrn(none, medium and high infestation area).rnResults showed that from all the sample species P. hysterophorus was found the most abundantrnin grazing land. On the contrary, the majority of the other species account for less than 5% ofrnrelative abundance. According to Partial Redundancy Analysis (RDA) 59.8% of the variation inrnspecies data was observed in the first four PCA axes and 11.5% of the variation with the first twornaxes. Biplot diagram indicates that P. hysterophorus weed is negatively correlated with thernmajority of species. According to the patch test the abundance of the sample species isrnstatistically significant at P=0.01 between none and high infested area of P. hysterophorusrnwhereas the difference between the height of the species is insignificant at P=0.05. Thernpercentage of sand, clay and silt is statistically significant at P=0.01, P=0.01 and at P= 0.05,rnrespectively, and the pH and moisture content of the sample soil is statistically significant atrnP=0.05 and insignificant at P= 0.05 value, respectively. The average number of nematodes inrnnone, medium and high infested field of P. hysterophorus were statistically significant at P=0.05.Field survey results showed that all the sample farmers were aware of P. hysterophorus, its waysrnof introduction into their locality, the agents facilitating its dissemination and places where P.rnhysterophorus is densely populated. In the study areas, more than 90% of the respondents noticedrnthat P. hysterophorus was the most abundant and threat to the loss of biodiversity. Accordingly,rnthe grass species Cleome gynandra, Amaranthus graecizans, Cucumis dipsaceus, Bidens pilosa,rnLaunaea intybacca, Enteropogon macrostachyus, Eragrostis cilianensis, Euphorbia indice andrnBoerhavia coccinea are endangered by P. hysterophorus.rnP. hysterophorus weed can cause serious loss on the production and productivity of crops,rnhuman health and biodiversity. Hence it has a significant effect on the economic development ofrnthe study area. Integration of different control methods are therefore needed to prevent andrncontrol the danger of P. hysterophorus.