BACKGROUND: A habit of lying-down after eating is known as a risk factor of reflux esophagitis. However the association between gastrointestinal disorders and a postprandial lying-down habit has not yet been identified. Some people believe that lying-down after meals is helpful for their health. We intended to investigate the relationship between such a habit and the health lifestyles, gastrointestinal symptoms, disorders using a questionnaires and gastrofiberscopic results of patients who visited our general health screening center. METHODS: We examined 1,030 subjects (the frequent postprandial lying-down group was 576 persons (57.7%), the rare group was 436 persons (42.3%) who visited our general health screening center for a routine check-up including a gastrofiberoscopy during the period between January 2001 to December 2002. After frequency matching by age and sex, health lifestyles (such as smoking, alcohol consumption, exercise, eating habits, night time sleep duration and awakening frequency, nap, and coffee intake), gastrointestinal symptoms (dyspepsia, epigastric pain, heart burn, chest pain, and constipation) and gastrofiberoscopic findings were compared using results from the questionnaires and gastrofiberscopic findings. Factors such as gastritis and reflux esophagitis were set as dependent variables, while postprandial lying-down was set as an independent variable. The frequent postprandial lying-down group and the rare group were analysed through stepwised multiple logistic regression analysis. RESULTS: Subjects with a frequent postprandial lying- down habit showed a significantly greater degree in alcohol consumption (P=0.010), irregular eating habits (P<0.001), eating between meals (P<0.001), napping (P<0.001), and night time awakening frequency (P= 0.016) than the rare group did. In addition, chest pain (P=0.031) and constipation (P=0.010) were more common in the frequent postprandial lying-down group. However, prevalence of dyspepsia (P=0.147), epigastric pain (P=0.085), and heartburn (P=0.700) showed no differences between the two groups. Being controlled with age, sex, education level, body mass index, and life style factors, postprandial lying-down group showed higher prevalence ratios in erythematous gastritis (OR 1.59; P=0.090), atrophic gastritis (OR 1.71; P= 0.059), and reflux esophagitis (OR 1.78; P=0.103). CONCLUSION: A postprandial lying-down habit is associated with undesirable lifestyles and some gastrointestinal disorders. Therefore, a modification of the postprandial lying-down habit should be recommended. Further investigation is needed to clarify the causal relationships between a postprandial lying down habit and gastrointestinal symptoms and disorders.