All studies confirm IBS is one of the most common problems in medical practice, and the most common in gastroenterologic practice, underdiagnosed in many cases, misdiagnosed in others. In our country there are no studies published to describe the prevalence of symptoms of IBS. Our objective was to evaluate the prevalence of Manning s Criteria, in an apparently healthy population, of high socioeconomical level, from Lima. We carried-out a cross-sectional study of prevalence in 300 subjects from 5 districts of higher socioeconomical level of Lima. We found 78 persons with lower bowel symptoms (26%). The most frequent symptom-criterion in this population was mucus in stools, meanwhile the least frequent was the increase in frequency. We do not find differences between frequency of symptoms with depression associated, sex, age, nor districts. Our frequency of symptoms is not in accord with traditionally described in this syndrome.