|The retrospective cohort study aim to compare the incidence rate of cardiovascular adverse events in osteoarthritis and rheumatoid arthritis patients who were prescribed with either selective COX-2 inhibitor (Celecoxib) or conventional non-steroidal anti-inflammatory drugs (NSAIDs) or were not prescribed with medication at Roi-Et hospital during October 1st, 2002 to September 30th, 2007. The validated electronic medical database and medication records were used to collect the data. Of 7,224 patients, 5,195 patients were included in the study. Three thousand two hundred and fifty eight patients received NSAIDs and 575 patients received Celecoxib. Cardiovascular events occurred in 13, 14 and 47 patients who were treated with Celecoxib, NSAIDs and no-medication respectively. The incident rate of cardiovascular events in Celecoxib group was not different from that of NSAIDs-naïve group. Compared with NSAIDs-naïve group, NSAIDs group is less likely to have cardiovascular adverse events than NSAIDs-naïve group (relative risk = 0.13, 95%CI = 0.07 - 0.23). Compared with Celecoxib group, NSAIDs group is less likely to have cardiovascular adverse events than Celecobix group (relative risk = 0.19, 95% CI = 0.09 – 0.40).