Background & Aims: Atopic dermatitis is a common allergic disease recognized as a threat to public health. Atopic dermatitis is often observed in people with individual or family history of allergic diseases. Due to the importance of this disease and its early diagnosis, and the very limited number of studies on this topic, the current study was performed on the prevalence of atopic dermatitis on infants under 2 years of age. Methods: This was an analytic cross-sectional study from January 2010 to February 2011. All infants referred to Hazrat Rasoul Akram Hospital (Tehran, Iran) for vaccination were enrolled in the study. Patients with atopic dermatitis, by permission of their parents, underwent Prick test for identification of the allergy type. Results: In the present study, 380 infants were enrolled with mean age of 9.9 ± 6.6 months (217 boys and 163 girls). Patients were classified into two groups based on atopic dermatitis (48 positive for eczema and 332 negative for it). Of the 48 subjects of the positive group, 31 agreed to take the Prick test. The results showed that 11 patients (35.5%) were allergic to cow milk, 6 patients (19.3%) to almond, 4 patients (12.9%) to rice and egg's yolk, 3 patients (9.7%) to egg white, 2 patients (6.5%) to fish, soybean, potato, and sesame, and 1 patient (3.2%) to wheat flour. Conclusion: It seems that the outbreak of atopic dermatitis in children is relatively high, and avoidable factors play a role in its occurrence. Hence, based on the examined Prick tests, It seems that the occurrence and exacerbation of the disease can be controlled and its progression into asthma prevented by decreasing or removing food allergens and factors involved in the patient's disease process.