This study was initiated to assess whether dietary diversity and household food insecurity are associated with nutritional status of children western Oromia, Ethiopia. A community based cross sectional study was employed in September, 2020. Multi stages sampling methods were employed. Dietary diversity score, Food Insecurity and anthropometric data were also used. Data was analysed using SPSS version 20.0. Logistic regression analyses were also carried out. The study also found that the prevalence of underweight, stunting and wasting among children was 19.6%, 27% and 11.8%, respectively. The finding of this study showed that poor wealth index and food insecurity were determinants of underweight. Moreover, child birth order above three years, no antenatal care visit, no consumption of wild edible foods and low dietary diversity were determinants of stunting. Furthermore, this study indicated that having a history of sickness, no antenatal care visit and low dietary diversity were determinants of wasting. This study concluded that the prevalence of under-nutrition among young children in the study area is high. Therefore, a community based nutrition education should be done to overcome the problems of under nutrition of children in the study area.