Prevalence estimates for irritable bowel syndrome from surveys in Western countries are 4.4% to 22%, generally higher in women than men, and only a minority seek health care. There are few studies of bowel patterns in Asian countries. We conducted a survey of a nonpatient population in Ho Chi Minh City, Vietnam, to determine bowel patterns and the prevalence of bowel dysfunction. A forced-choice, self-report questionnaire was distributed to 738 predominantly health care workers, as well as patient relatives, at Cho Ray Hospital in Ho Chi Minh City and returned by 411 (response rate of 55.7%). Results were analyzed for men and women using Student's t-test for continuous variables and chi-square test for categorical variables. Subjects were 53.6% female, with a mean age of 27.7±6.9 years. Overall perception of health was excellent/very good in 13.6%, good in 54.2%, and fair/poor in 32.1% (males, 17.1%, 51.3%, and 31.5%, vs. females, 10.6%, 56.7%, and 32.7%; P=NS). The mean number of stools reported per week was 6.5 (males, 6.6, vs. females, 6.4; P=NS) and ranged between 3 and 21 stools per week in 95.5%. The frequency of irritable bowel syndrome symptoms (using Rome I criteria) was 7.2% (95% CI=4.8–10.1), with males at 4.8% (95% CI=2.2–8.9) vs. females at 9.2% (95% CI=5.7–13.9) (P=0.08). Of the subjects with irritable bowel syndrome symptoms, 6 of 29 (20.7%) had seen a physician for bowel symptoms. There were no gender differences in reported infrequent stool (12.0%), frequent stool (11.3%), hard stool (17.5%), loose stool (6.5%), straining (14.5%), incomplete emptying (16.2%), bloating (15.0%), urgency (10.0%), or mucus (2.7%). In conclusion, this survey of a nonpatient population in Vietnam showed that irritable bowel syndrome symptoms as defined by Rome criteria were common and that there were no significant differences between sexes in either stool frequency or prevalence of irritable bowel syndrome, unlike previous studies from the United States. The prevalence of irritable bowel syndrome in Vietnam in this study was in the lower range of reported data from Western countries, possibly in part related to the use of the Rome criteria. Only a minority of subjects with irritable bowel syndrome symptoms reported seeking health care for these symptoms.