Adequate separation of the omentum from the transverse colon mesentery, during D2 radical gastrectomy, is usually difficult and often time-consuming due to anatomic variations. The aim of this prospective study was to compare the electrocautery dissection technique with hydrodissection-facilitated electrocauterization for the separation of the greater omentum from the superior layer of the transverse mesocolon in gastric cancer patients undergoing D2 radical gastrectomy. The time taken to separate the greater omentum from the superior layer of the transverse mesocolon, and the number and extension of iatrogenically-created mesocolonic defects were assessed. Forty patients were prospectively randomized into 2 groups. Separation of the greater omentum from the superior layer of the transverse mesocolon was achieved in Group I (n = 20) patients by the monopolar cauterization dissection technique whereas in Group II (n = 20) patients by the hydrodissection-facilitated monopolar cauterization. No significant difference was found between the 2 groups in terms of age, gender, body mass index (BMI), type of surgical technique, or the number of resected lymph nodes (P > 0.05). The difference between the 2 dissection techniques was not statistically significant when compared according to the number of iatrogenic mesocolonic defects, extension of the defects, or the time period required for the separation of greater omentum from the superior layer of the transverse mesocolon (P > 0.05). The overall survival was not significantly different between the 2 dissection techniques ( P > 0.05). Hydrodissection is a safe technique that can be applied as an adjunct to electrocauterization to facilitate the dissection in the correct plane during resection of the mesogastrium.