This study was designed to compare the long-term results of straight and J-pouch coloanal anastomoses after resection of rectal cancers located in the critical position of 5-6cm from the anal verge.The subjects of this study were 81 patients who underwent radical resection of rectal cancers located 5-6 cm from the anal verge, followed by straight or J-pouch coloanal anastomosis, performed in 41 and 40 patients, respectively. Careful clinical and manometric follow-up was conducted and the results were compared.There were no differences in the incidence of local recurrence, the disease-free survival rate, postoperative stool frequency, continence, sphincter pressures, or functional length between the two groups. Both groups had a high incidence of clustering or fragmented defecation; however, the J-pouch patients had better urgency control, a greater capacity before feeling the urge to defecation, superior rectal tolerance, and better compliance.Both straight and J-pouch coloanal anastomoses are oncologically and functionally acceptable for the treatment of rectal cancer located 5-6cm from the anal verge, but the J pouch has slight superiority in urgency control, as a result of larger urge threshold and tolerable volume, and better compliance. The reason for the high incidence of clustering defecation in both groups needs to be investigated.