We evaluated the effect of intestinal anastomosis without resection on gut morphometry (muscle thickness, villus height, and crypt depth), growth indices (DNA, protein, and protein:DNA ratio), and disaccharidase activity (maltase, sucrase, and lactase) in the growing animal. A group of 10 weanling Sprague-Dawley rats at 21 days of age was subjected to intestinal transection and anastomosis in the upper jejunum, 10 cm distal to the ligament of Treitz. A second group of 10 similar rats was used as a control group. All rats were fed a regular diet and kept under the same conditions. They were sacrificed 2 weeks later. Body weight, intestinal weight, and intestinal length measurements were obtained. The intestine was divided into two sections: preanastomotic (section A) and postanastomotic (section B) in the surgery group and equivalent sections A and B in the control group. Specimens were subjected to morphometric evaluation and mucosal scrapings for biochemical analysis. Despite significant weight gain in the control group, there were no differences in intestinal length, intestinal weight, and mucosal weight between the two groups. Muscle thickness, villus height, and crypt depth were significantly increased in the preanastomotic segment. Protein and DNA were also higher in the preanastomotic segment, but the protein:DNA ratio was less affected. There was significantly decreased enzymatic activity in the preanastomotic segment. Intestinal anastomosis has a significant effect on gut growth and maturation in the growing animal and may have important implications in the postoperative management of newborns and infants following intestinal surgery.