The purpose of this study was to evaluate the relationship of large diverticulum (>3 cm) and volvulus of the small bowel (SB) in adults. A computer search of the medical records between January 1995 and December 2002 revealed 94 surgically proved cases of small bowel volvulus in adults. We reviewed the surgical records and recorded any specific condition found during laparotomy. The control group included 107 consecutive patients receiving a laparotomy with a diagnosis other than SB volvulus. In the 94 surgically proved cases of SB volvulus, the surgical records described presence of adhesion in 47 cases, adhesions around large SB diverticulum (>3 cm) in 5 cases, coexistence of large SB diverticulum and adhesions around the narrowed mesenteric root in 4 cases, large SB diverticulum without a specific description of the presence of adhesion or narrowed mesenteric root in 24 cases, narrowed mesenteric root without large SB diverticulum in 3 cases, internal hernia in 4 cases, tumors in 3 cases, and absence of any specific lesion in 4 cases. Only one case was found to have a large SB diverticulum in the control group. The incidence of large SB diverticulum in SB volvulus of adults was 35% (33/94), significantly higher than that of the control group (1%, 1/107) (p < 0.01). Large diverticulum of the small bowel might play a contributing role in the occurrence of SB volvulus in adults.