AbstractStool weight and transit time through the gut were measured in 4 groups of 30 men, aged 50–59 years, randomly selected from populations in urban (Copenhagen) and rural (Them) Denmark and urban (Helsinki) and rural (Parikkala) Finland. These populations exhibited a 3–4 fold difference in risk for large bowel cancer. Mean transit time (37±I hours, Copenhagen; 43±1 hours, Helsinki; 40±1 hours. Them; 37±1 hours, Parikkala) was not significantly different among populations, but average 24‐hour stool weights (136±13 g, Copenhagen; 176±17 g, Helsinki; 169±16 g, Them; 196±15 g, Parikkala) were different and had a significant inverse relationship to total large bowel cancer incidence, with larger stool weights being found in the low‐risk population. A high proportion of study subjects, especially in Finland, were found to be taking medication or to have a history of gastrointestinal illness, but neither of these variables related to bowel habit.