Purpose: Postoperative nausea and vomiting (PONV) is one of the most common complications of anesthesia. PONV prolongs the hospitalisation and recovery time. We compared the antiemetic effect of dexametasone with metoclopramide in patients who had undergone laparascopic colecystectomy. Methods: Forty-five patients were randomly divided into three groups with 15 patients in each group. Group K (control group) received no antiemetic drug. Group M received iv 10 mg metoclopramide 10 minutes before extubation; Group D received iv 5 mg dexamethasone 10 minutes before extubation. Results: The frequency of nausea and vomiting was no different from group at 6 th hour. At the 4 th hour the frequency of nausea and vomiting in group K was not different from group M and D. In other time intervals no significant difference was seen between the groups (P<0.05). The score of nausea and vomiting exhibited no significant variation between the groups. Conclusions: Our study has shown that a single dose of 5 mg dexamethasone can be used in PONV without significant side effects.