We experienced 12 consecutive cases of complete bowel obstruction due to primary colorectal cancer. Among these patients, temporary loop colostomy (loop C) was performed within the resection zone for the primary tumor in 10 cases, and Hartmann's operation was performed in two cases. The loop C was located in the sigmoid colon in five cases and on the left side of the transverse colon in five cases. The interval until radical resection was from 13 to 35 days (mean: 20 days), the duration of surgery was from 2 h 5 min to 4 h 55 min (mean: 4 h 7 min), and the length of resected bowel ranged from 22.5 cm to 51.2 cm (mean: 29.8 cm). Mild wound infection was observed in two cases. Dukes' clinical stage was as follows: A in 0 case, B in 5 cases, C in 6 cases and D (distant metastasis) in 1 case. We have achieved good results over the past two years without performing standard loop C on the right side of the transverse colon.