Pyloric stenosis is an uncommon but important gastric outflow disease. Heineke-Mikulicz (H-M) pyloroplasty is one of the pyloroplasty techniques used for the treatment of such diseases. A laparoscopic pyloroplasty is an effective and preferred alternative technique to conventional surgeries. This study aims to compare the duration of surgery, surgical stress level measurement, and postoperative pain in laparoscopic H-M pyloroplasty in normal dogs with a conventional pyloroplasty technique. Eight intact adult mixed breed dogs (5 females and 3 males) were used in this study. Animals were randomly divided into two groups of conventional open (n = 4) and laparoscopic (n = 4) H-M pyloroplasty. Blood glucose concentration, plasma cortisol level, as well as pyloric features including a pyloric lumen, pyloric diameter, pyloric width with ultrasonography, and gastric emptying time with contrast radiography and the University of Melbourne Pain Scale (UMPS) value, were measured in both groups. The mean operation time in the laparoscopic group was longer than that of the conventional group (55.00 ± 15.00 vs. 35.00 ± 4.56 min); however, this difference was not statistically significant. Blood glucose concentration in the laparoscopic group elevated rapidly until 3 hours after the operation and then decreased in 24 hours while blood glucose concentration in the conventional group slowly increased until 24 hours. The UMPS value at 3 hours after conventional H-M pyloroplasty was higher than that of laparoscopic H-M pyloroplasty (19.25 ± 0.75 vs. 6.50 ± 0.96, p < 0.001). Gastric emptying time significantly decreased in both groups. According to the results, in addition to reducing pain and stress, laparoscopic H-M pyloroplasty decreased gastric emptying time in all patients with no morbidity and appears to be a less invasive alternative technique for the management of gastric outflow disease.