ABSTRACT: BACKGROUND:Goiter is a major public health problem in Ethiopia. Even though there were studies done on goiter in Ethiopia, there was little evidence in the eastern part of the country. Therefore, the aim of this study was to assess the prevalence of goiter and its associated factors among school-age children in Anchar district of Eastern Ethiopia. METHODS:A school based cross-sectional study was conducted from February 13 to 30, 2017. Multistage sampling method was used to select 418 children aged 6-12 years. Data were collected using a questionnaire. Children were examined for the presence or absence of goiter based on the criteria of the World Health Organization (WHO). Salt samples were tested using a rapid test kit. Data were entered to EpiData version 3.1 and exported to SPSS version 22.0 for analysis. Bivariate and multivariate logistic regression models were fitted; Crude Odds Ratio (COR) and Adjusted Odds Ratio (AOR) with 95% Confidence Interval (CI) were computed. Level of significance was determined at p-value less than 0.05. RESULTS:The total goiter prevalence rate was 51.8% (CI: 46.9%, 56.8%). Father's education (AOR = 1.87, CI: 1.06, 3.30), type of salt used (AOR = 2.09, CI: 1.13, 3.88), iodine level of salt (AOR = 2.77, CI: 1.11, 6.89), frequency of milk consumption (AOR = 3.65, CI: 1.63, 8.20), frequency of cabbage consumption (AOR = 7.74, CI: 4.48, 13.39), eating status of eggs (AOR = 3.16, CI: 1.54, 6.50), and eating status of dark green vegetables/fruits (AOR = 2.14, CI: 1.17, 3.93) were factors associated with goiter among school-age children. CONCLUSIONS:The total goiter prevalence rate was very high. Therefore, the health and education sectors of the study area should work hand in hand to improve the awareness of the community about goiter, iodized salt and iodine rich foods.