Various stapling devices have been applied to create the small gastric pouch necessary for effective weight loss in morbid obesity, but it is unclear as to which staple line arrangement provides the most reliable gastric wound healing. Five variants of staple lines (Groups I-V) were used to create a gastric partition in 47 adult mongrel dogs (20-30 kg). Staple-line arrangements were as follows: Group I (n = 10)-two superimposed double rows (TA-90), Group II (n = 10)-prototype staple line of four rows 2.03 mm apart, Group III (n = 12)-two double rows of staples 6.5 mm apart, Group IV (n = 10)-prototype staple line of two double rows of staples 0.64 mm apart, and Group V (n = 5)-a single double-row staple line (TA-90). Staple lines were examined at 2, 4, 8, and 13-16 weeks for evidence of healing, histology, tensile strength, and collagen (hydroxyproline) content. Significant differences in staple-line disruption rates were found between all groups (χ2, P < 0.01). The prototype four-row staple line (Group II) had the most significant parameters of wound repair determined by biochemical evidence of wound healing and enhanced tensile strength. Staple-line arrangement appears to be an important determinant of gastric wound healing and may influence the rate of postoperative gastric partition disruption. © 1987.