This study is based on secondary data from HICES and WMS 2004/5 collected by CSA. The study has tried to examine the extent of vulnerability to poverty of households in rural Oromiya. It further looks through the determinants of vulnerability to poverty. An estimate of vulnerability to poverty shows that 17.93 percent of the non poor are highly vulnerable. The mean vulnerability for highly vulnerable households is found to be 0.62. The Logit model is used to investigate the determinants of vulnerability to poverty. From the estimation result of the model larger household sizes and illiterate head of household significantly increase the probability of the household to be vulnerable. Therefore ex ante measures to prevent households from becoming poor as well as ex post measures to alleviate those already in poverty should be combined in designing poverty reduction strategies.