We investigated the relationship between gastrointestinal (GI) transit and motility during postoperative ileus in dogs undergoing a single laparotomy. We combined X-ray radiography for a GI transit study with chronically implanted force transducers (FTs) for a GI motility study. Radio-opaque markers made of polyethylene and steel wires or barium sulfate were used to examine solid substance transit or liquid substance transit. For a while after the end of the operation, postoperative ileus was observed, with weak irregular contractions of the GI tract. Transmission of the contractions to the lower GI tract was then observed. The start point of interdigestive migrating contraction (IMC)-like motility was observed in the order of small intestine (I-IMC), duodenum (D-IMC), and stomach (G-IMC), and IMC proceeded gradually after the operation. The gastric emptying time of a solid marker was 73.6 +/- 2.3 h (n = 5), and depended on the time of first occurrence of G-IMC (r = 0.674, p = 0.006). The gastric emptying of the liquid marker was finished before the time of the first occurrence of G-IMC, and its small intestinal transit time correlated with the time of the first occurrence of G-IMC (r = 0.888, p = 0.018). Using combined X-ray radiography and FTs we found that recovery from postoperative ileus was aided by GI motility in which contractions were transmitted from the stomach to the lower GI tract, like IMC.