This study investigated the factors affecting the length of the minilaparotomy incision (LOMI) in laparoscopy-assisted distal gastrectomy with Billroth I reconstruction. By using abdominal computed tomography scans, we measured the thickness of the rectus muscle (TRM), the thickness of the abdominal wall (TAW), and the distance from the gastroduodenal artery to the skin (GDAS) in 80 patients with early gastric cancer who had undergone surgery. There were positive correlations between the LOMI and body mass index (BMI), TRM, and TAW, and the LOMI increased significantly in patients with BMI > or =25 kg/m2, TAW > or =2.1 cm, and TRM > or =1.0 cm. These observations suggest that patients with two or more of the following clinical factors, BMI > or =25 kg/m2, TAW > or =2.1 cm, and TRM > or =1.0 cm, may require surgical procedures other than laparoscopy-assisted Billroth I, such as total laparoscopic intracorporeal Billroth I, Billroth II, or uncut Roux-en-Y reconstruction.