Anemia is one of the main conditions that impose an adverse impact on the socioeconomic state of any country; however, evidence on the prevalence of anemia is scant in Northeastern Iran. This study was conducted to determine the overall and age- and sex-specific prevalence of anemia in the city of Mashhad, Iran. In a cross-sectional, population-based survey, 1675 individuals aged 1-90 years (29.1±18.5 years) were selected from approximately 2.4 million residents by a multistage cluster sampling method during May to September 2009. Blood samples were evaluated to determine erythrocyte indices and anemia was defined according to hemoglobin (Hb) levels based on World Health Organization (WHO) guidelines. The prevalence of anemia was 9.7% with considerable difference between both sexes; 6.2% and 12.7% in males and females, respectively (P<0.001). The higher prevalence of anemia was detected in females of 15-54 and ≥ 65 years old (16% and 12.5%, respectively). However, the higher rates were observed in males 65 years and older as well as boys below 5 years old (16.3% and 14.6%, respectively). Current findings show that anemia is a considerable public health problem in the population of Mashhad, Iran, especially among the pre-school children, adult women and the elderly. Great attention should be paid to the pre-school boys who are more affected by anemia than what was previously assumed