Prevalence of lactose intolerance is not clear due to diversity and methodological limitations in the published literature [1].Studies from the Middle East region, especially Kuwait, are limited.Lactase activity assay in small bowel biopsy is the gold standard for diagnosing lactose malabsorption,but it is not used as being invasive with availability of non-invasive tests [2].Aims:We aimed at comparing the prevalence of lactose intolerance among Kuwaitis and non-Kuwaiti expats resident in Kuwait.117 consecutive patients were recruited from our outpatient clinics (52 Kuwaitis and 65 non-Kuwaitis).Patients were enrolled if they have symptoms of lactose intolerance.Patients were subjected to upper gastrointestinal endoscopy and two post bulbar duodenal biopsies were tested using the Quick Lactase Test assays (Biohit Oyj, Helsinki, Finland) [5].Results were reported and interpreted according to manufacturer recommendations.Results: Our study included 117 patients (44.4% Kuwaitis and 55.6% non-Kuwaiti) with mean age (±SD)42.1(±13.5) years including 70 females (59.8%).diarrhea was present in(14.5 %),abdominal pain in(65.8 %), abdominal bloating in(53.8 %)and flatulence in(36.8 %)of the studied groups.There were no significant differences between Kuwaitis and non-Kuwaitis in regard to symptoms of lactose intolerance or demographic data. Lactose intolerance was positive in 96 patients(82.1%),of which severe lactose intolerance was reported in 65 cases (67.7 %)while mild lactose intolerance was reported in 31 cases(32.3%).All patients express symptoms of lactose intolerance; however only flatulence was significantly increased in patients having severe lactose intolerance.Conclusion Lactose intolerance is highly prevalent among Kuwaitis and non-Kuwaiti patients having symptoms suggestive of lactose intolerance.Flatulence was the most significant symptoms associated with lactose intolerance in Kuwait.