Abstract Objective: Laparoscopic trocar-cannula systems of different design but similar internal diameter result in incisions of varying dimensions. Such variations might affect the incidence of incisional complications, such as dehiscence and hernia. We developed a system to measure associated fascial defects and then used the techniques to compare the defects resulting from different trocar-cannula systems. Methods: This was a randomized, observer-blinded study. Six laparoscopic trocar-cannula systems of similar diameter (12 mm) were tested (two pyramidal, two blunt conical, and two cutting-dilating) using a white swine model. All systems were inserted into each of 12 subjects, with location designated by random allotment (total 72 insertions). The fascial defects were exposed and then directly measured for incisional length and area by an observer blinded to the system used. Means of each outcome variable (incisional length and area) were compared using factorial analysis of variance. Results: The values for mean incisional areas were as follows: cutting-dilating 28.73 mm 2 and 31.09 mm 2, pyramidal 18.25 mm 2 and 26.75 mm 2, and blunt conical 10.00 mm 2 and 12.33 mm 2. Mean maximal incisional lengths were similar among all trocar-cannula systems. Conclusion: Blunt conical trocar-cannula systems resulted in significantly smaller fascial defects compared with the widely used pyramidal and the two cutting-dilating trocar-cannula systems tested. These differences have potential clinical implications. For example, smaller fascial defects could reduce risk of incisional hernia and dehiscence.