AIM:To investigate and compare frequencies of serumpositive cagA in patients from two separate regions of Turkeywho were grouped according to the presence of peptic ulcerdisease or non-ulcer dyspepsia.METHODS:One hundred and eighty Helicobacter pylori-positive patients with peptic ulcer disease or non-ulcerdyspepsia were included in the study.One hundred andfourteen patients had non-ulcer dyspepsia and 66 had pepticulcer disease (32 with gastric ulcers and/or erosions and 34with duodenal ulcers).Each patient was tested for serumantibody to H.pyloricagA protein by enzyme immunoassay.RESULTS:The total frequency of serum positive cagA inthe study group was 97.2 %.The rates in the patients withpeptic ulcers and in those with non-ulcer dyspepsia were100% and 95.6%,respectively.These results were similarto those reported in Asian studies,but higher than thosethat have been noted in other studies from Turkey andWestern countries.CONCLUSION:The high rates of serum positive cagA inthese patients with peptic ulcer disease and non-ulcerdyspepsia were similar to results reported in Asia.The factthat there was high seroum prevalence regardless of ulcerstatus suggests that factors other than cagA might beresponsible for ulceration or other types of severe pathologyin H.pylori-positive individuals. AIM: To investigate and compare frequencies of serumpositive cagA in patients from two separate regions of Turkeywho were grouped according to the presence of peptic ulcerdisease or non-ulcer dyspepsia. METHODS: One hundred and eighty Helicobacter pylori-positive patients with peptic ulcer disease or non -ulcerdyspepsia were included in the study. One hundred and fourteen patients had non-ulcer dyspepsia and 66 had pepticulcer disease (32 with gastric ulcers and / or erosions and 34 with duodenal ulcers). Each patient was tested for serumantibody to H. pyloricagA protein by enzyme The total frequency of serum positive cagA inthe study group was 97.2%. The rates in the patients withpeptic ulcers and in those with non-ulcer dyspepsia were 100% and 95.6%, respectively. The results were similarto those reported in Asian studies , but higher than thosethat have been noted in other studies from Turkey and Western countries. CONCLUSION: The high rates of serum positive cagA inthese patient s with peptic ulcer disease and non-ulcerdyspepsia were similar to results reported in Asia.The factthat therewas high seroum prevalence regardless of ulcerstatus suggests that factors other than cagA might beresponsible for ulceration or other types of severe pathologyin H.pylori-positive individuals.