BACKGROUND Ileocolic anastomoses are commonly performed for right-sided colon cancer and Crohn's disease. The anastomosis may be constructed using a linear cutter stapler or by suturing. Individual trials comparing stapled versus handsewn ileocolic anastomoses have found little difference in the complication rate but they have lacked adequate power to detect potential small difference. To our knowledge, this is the first systematic review specifically investigating ileocolic anastomosis. OBJECTIVE To compare outcomes of ileocolic anastomoses performed using stapling and handsewn techniques. The hypothesis tested was that the stapling technique is associated with fewer complications. METHODS MEDLINE, EMBASE, Cochrane Colorectal Cancer Group specialised register SR-COLOCA, Cochrane Library were searched for randomised controlled trials comparing use of a linear cuter stapler with any type of suturing technique for ileocolic anastomoses in adults from 1970 to 2005. Abstracts presented to the following society meetings between 1970 and 2002 were handsearched: American Society of Colon and Rectal Surgeons, the Association of Coloproctology of Great Britain and Ireland, European Association of Coloproctology. METHODS Randomised controlled trials comparing use of linear cutter stapler (isoperistaltic side to side or functional end to end) with any type of suturing technique in adults. METHODS Eligible studies were selected and their methodological quality assessed. Relevant results were extracted and missing data sought from the authors. RevMan 4.2 Analysis version 1.0.5 was used to perform meta-analysis when there were sufficient data. Sub-group analyses for cancer and inflammatory bowel disease as indication for ileocolic anastomoses were performed. RESULTS After obtaining individual data from authors for studies that include other anastomoses, six trials (including one unpublished) with 955 ileocolic participants (357 stapled, 598 handsewn) were included. The three largest trials had adequate allocation concealment. Stapled anastomosis was associated with significantly fewer anastomotic leaks compared with handsewn (S=5/357, HS=36/598, OR 0.34 [0.14, 0.82] p=0.02). One study performed routine radiology to detect asymptomatic leaks. For the sub-group of 825 cancer patients in four studies, stapled anastomosis led to significant fewer anastomotic leaks (S=4/300, HS=35/525, OR 0.28 [0.10, 0.75] p=0.01). There were too few Crohn's disease patients to perform sub-group analysis. All other outcomes: stricture, anastomotic haemorrhage, anastomotic time, re-operation, mortality, intra-abdominal abscess, wound infection, length of stay, showed no significant difference. CONCLUSIONS Stapled functional end to end ileocolic anastomosis is associated with fewer leaks than handsewn anastomosis.