Background: Chronic idiopathic urticaria is defined as urticaria, which lasts for more than 8 weeks and has no apparent etiology. The aim of this study was to examine the causal role of Helicobacter pylori infection in chronic idiopathic urticaria. Methods: Fifty-six patients with chronic idiopathic urticaria and a negative response to skin prick test for common aeroallergens were selected. They were examined for H pylori infection using a serologic test and urea breath test, and were divided into three groups. The first group included H pylori-positive patients (n=23), who did receive eradication regimen for two weeks. The second group comprised of H pylori-positive patients (n=15), who did not have the indications for anti H pylori treatment, and were not treated. The third group included H pylori-negative patients (n=18), who received no treatment. The patients were studied for signs and severity of urticaria. Results: In the first group, urticaria improved partially and completely in 74% (n=17) of cases. In the second group, urticaria did not improve in 60% (n=9), and improved partially in 40% (n= 6) of cases. In the third group, urticaria did not improve in 61% (n=11), and improved partially in 39% (n=7) of cases. Patients, who had a higher titer of urea breath test and longer period of symptomatic urticaria, had better response than the others. Conclusion: The findings suggest that anti-H Pylori treatment is significantly effective in the treatment of chronic idiopathic urticaria. H Pylori eradication can be suggested as a method for treating urticaria, if the urea breath test is positive.