The objective of this study was to estimate the rate of postoperative nausea and vomiting in patients receiving antiemetic drugs and its risk factors at Hanoi Medical University Hospital. 486 patients (male: 47,1 percent, female: 52.9 percent) were selected to the study from all types of surgery. All patients had peri-operatively corticoid (dexamethasone or solumedrol) and prizenton for preventing postoperative nausea and vomiting. The rate of nausea and vomiting was 17.10 percent during three days after surgery. Five risk factors of postoperative nausea and vomiting were determined: history of car sickness (OR = 3.3, 95 percent CI: 2.1 - 5.4), history of postoperative nausea and vomiting (OR = 3.1, 95 percent CI: 1.2 - 8.2), female gender (OR = 2.1, 95 percent CI: 1.3 - 3.4), non - smoking status (OR = 2.5, 95 percent CI: 1.2 - 5.2) and hypotension during surgery (OR = 2.1, 95 percent CI: 1.0 - 4.5). Only two independent risk factors were identified: history of car sickness (OR = 2.8, 95 percent CI: 1.6 - 4.9) and history of postoperative nausea and vomiting (OR = 3.0, 95 percent CI: 1.1 - 8.7).