BACKGROUND Alopecia areata is an immune mediated inflammatory hair loss, which occurs in all ethnic and age groups, and both sexes. However no significant etiology has been known for this disease. Helicobacter pylori (H. pylori) , is an organism colonized in gastric mucosa. This bacterium has been associated with certain extra-digestive dermatological conditions. The causal relationship between alopecia areata and H. pylori infection has been discussed in literature. Therefore, we conducted this study to evaluate the prevalence of H. pylori infection in patients with alopecia areata and assess the risk of this infection in patients with this disease in order to determine its potential roles in the physiopathology of this disease. METHODS Between 2014 and 2015, we prospectively studied 81 patients with alopecia areata and 81 healthy volunteers with similar age and sex. Patients without any history of H. pylori infection were included in the study and underwent urease breath test. All results were analyzed using SPSS software (version 21.0) and p value<0.05 was considered as statistically significant. RESULTS 81 patients and 81 controls with the mean age of 34.9±11.6 and 38.2±13.4 years were studied (p=0.097). 48 (59.3%) and 45 (55.6%) individuals were male, in cases and control groups respectively (p =0.634). The result of urea breath test (UBT) was positive in 43 (53.1%) patients in cases and 27 (33.3%) individuals in control group, which was significantly different (p =0.011). The risk of H. pylori infection in alopecia areata was 2.263 (95% CI: 1.199-4.273). CONCLUSION The results of our study showed significant difference between H. pylori infection in individuals with and without alopecia areata, which shows that H. pylori contamination may be effective in physiopathology of alopecia areata. Therefore these results should be tested in large multivariable cohorts and controlled trials to reach more accurate evidence in the future and to generalize this idea to larger population.