[Background]Anastomotic leakage is a serious complication after rectal surgery. The aim of this study was to assess the effect of waiting time during firing of stapling devices on optimal staple formation. [Methods]An endoscopic linear stapler (Echelon Flex 60 Endopath) with either a 60 mm blue or gold cartridge was applied to the cardiac and pyloric portions of 27 fresh porcine stomachs. Three different waiting times were used for the precompression and interstroke periods (0/0, 2/0, and 2/2 min). The staple line was divided into four portions (oral, anal and top, base), and the shape of each staple was evaluated. Optimal staple formation was also assessed using the circular stapler (CDH 29). [Results]Mean thickness of the cardiac and pyloric portions was 2.4 ± 0.35 mm and 4.0 ± 0.4 mm, respectively. The waiting time improved optimal staple formation for the blue cartridge, especially when it was used for the pyloric portion. Staple malformation was observed more commonly in the top portion than in the base portion; however, the former was improved by an interstroke waiting time. Staple formation using the circular stapler was satisfactory and not influenced by the prefiring waiting time or tissue thickness. [Conclusions]Employment of a waiting time improves optimal staple formation when the endoscopic linear stapler is used for challenging tissue.