Background: Iron-deficiency anemia (IDA) is a common clinical problem throughout the world and an enormous public health risk in developing and even in industrialized countries. Globally, the most significant contributor to the onset of anemia is iron deficiency. In Yemen, current rates of anemia among preschool aged children and pregnant women are 68.3% and 58.1% respectively. Aim: To determine the prevalence of iron deficiency anemia (IDA) in the first grade students in primary schools in Mathpah area, Sana'a city. Subjects and Methods: Out of 1300 primary schoolchildren registered in the selected schools, one hundred thirty students were systematically and randomly chosen, aged 5 -7 years (56 boys & 74 girls) from eight primary schools (three governmental basic schools and five private basic schools). Blood samples and questionnaire were collected. Complete blood count, serum iron, and serum ferritin were measured to assess iron deficiency and iron deficiency anemia. All data of the questionnaire and blood tests were analyzed using version 18 of SPSS. Results: In our study, the prevalence of anemia was 5.4%. The prevalence of iron deficiency and iron deficiency anemia were 31.5% and 3.9% respectively. Iron deficiency prevalence was 32.1% among boys and 31.1% among girls. There is a significant difference between governmental and private schools regarding iron deficiency (P= 0.037). Conclusion: Iron deficiency is prevalent among first grade students in primary schools in Mathpah area, Sana'a city. There is a significant difference between types of schools regarding to iron deficiency.