Background: Iodine is an essential element for growth and development and its inadequate intake leads to insufficient production of thyroid hormone. In developed countries iodine deficiency (ID) is one of the reformable factors. So, this study determined urinary iodine (UI) status of 8-10-year old school children in Yazd province during 2007 to 2016. Methods: This cross-sectional and descriptive study was conducted on 2236 students who were randomly selected from urban and rural regions with equal proportion of gender. Questionnaires were administered to gather the required descriptive data and then morning samples of urine were collected. Iodine concentration was determined with titration and acidic digestion. Data were analyzed through SPSS software. Results: During the study period, the percentage of students with UI of lower than 2 µg/dL, was zero and only 2.37 % of them had a UI level in the range of 2-4.90 µg/dL. Median of UI was 18.40 ± 7.70 µg/dL level of UI in normal range showed noticeable increase from 2013 to 2016. Level of normal UI in ten years was 79.02%. Conclusions: According to the results of this study, Yazd province was considered "IDD free" similar to some other provinces. Also, level of UI more than 30 µg/dL was decreased. It is clear that this approaches need continuous evaluation such as annual evaluation of UI in 8-10 years old students at province level and every five years evaluation at national level.