Background: Inappropriate infant and young child feeding (IYCF) practices are among major causes of childhood malnutrition, globally. Malnutrition in the first two years of child age results to permanent outcomes of growth failure, delayed sexual development, weakened immune system and poor cognitive development. In addition, malnourished children are at higher risks of dropping out in schools, which is costly to the education system of countries and households. This study was carried out to determine determinants of appropriate feeding practice by using three composite core world health organizations (WHO) IYCF practice indicators among children aged 6'23 months at Bale Zone, Southeast Ethiopia.  Methods: Community based cross sectional study design was used from January'June 2016 at Bale Zone, Southeast Ethiopia. An interviewer administered pre-tested and structured questionnaires were employed to collect the data. Multi'stage sampling technique was used to include the study subjects. Data was entered using Epi info version 3.5.3 and analyzed by SPSS version 20. Both bivariate and multivariate logistic regression analysis was done to filter determinant factors of appropriate feeding practice. All variables with P-values of < 0.2 in the bivariate were earmarked for the multivariate analysis. Both Crude Odds Ratio (COR) and Adjusted Odds Ratio (AOR) at 95% Confidence Interval (CI) were computed to determine the strength of association. In the multivariate analysis, variables with P'Values of ' 0.05 were considered as significantly associated with appropriate feeding practice. Results: A number of 801 mothers'children pairs were participated in the study. The overall prevalence of appropriate feeding practice was (26.8%) [95% CI: 0.24, 0.30]. It was significantly associated with child age (AOR= 0.17, 95% CI: 0.07, 0.41), child illness (AOR= 0.41, 95% CI: 0.24, 0.70), child growth monitoring participation (AOR=2.7, 95%CI: 1.39, 5.26), mothers' level of education (AOR= 0.03, 95% CI: 0.17, 0.54) and mothers' post natal care (PNC) visits (AOR= 2.3, 95% CI: 1.32, 3.90).  Conclusion: Appropriate infant and young child feeding practice was low in the study area. It was statistically associated with child age, child illness in the past one week of the interview, child growth monitoring participation in the previous one month of the survey, mothers' level of education and mothers' PNC service visits. Integrated efforts needed to increase mothers', and infant and young child health care utilization practices, and increasing mothers' level of education are important measures to improve IYCF practice in the predominantly agrarian society of Bale zone.