This study was conducted to evaluate the association between H. pylori infection and Iron deficiency anemia (IDA) among preschool children (age range: 40-75 months) at a tertiary referral hospital in Tehran.In a case-control study, the prevalence of H. pylori seropositivity was compared between 64 children with IDA diagnosis and 70 healthy non-anemic sex- and age-matched controls. Totally, 52 (81.3%) children with IDA and 10 (14.3%) non-anemic controls had a positive antibody level for H. pylori specific IgG and the difference between two groups was statistically significant (P<0.0001). H. pylori infection had a significant high prevalence among preschool patients with IDA. Eradication of H. pylori infection is recommended for patients with refractory IDA.