Study objective: Dexmedetomidine is widely used during surgery. Recent studies have demonstrated that dexmedetomidine administered perioperatively is associated with lower postoperative mortality and complications in patients undergoing cardiac surgery. Design: This study was designed to investigate the effects of dexmedetomidine during cardiac surgery in Chinese patients. Patients/Interventions: We conducted a retrospective review of 1477 consecutive patients who underwent cardiac surgery at our institution. Of these patients, 1077 received dexmedetomidine during their surgery (dexmedetomidine group) and 400 did not (control group). All patients were followed for 1 year. Their short- and long-term outcomes were compared by the inverse-probability of treatment weighted adjustment to reduce treatment selectmen bias. Propensity-score matching yielded two well-matched groups for further comparison. Main results: After adjusting for differences in baseline risk factors with the inverse probability of treatment weighting, the risk of perioperative mortality (Odds ratio [OR]:1.02; 95% confidence interval [CU]:0.32 to 3.28, P = 0.97) and cardiovascular complications were not significantly different between the two groups. After 1 year of follow-up, the two groups showed no differences in mortality (hazard ratio [HR]:0.70; 95% CI 0.28 to 1.73, P = 0.44) and major adverse cardiovascular and cerebrovascular events (MACCE) (HR 1.08; 95% CI 0.69 to 1.68, P = 0.74).However, postoperative atrial fibrillation was lower in the dexmedetomidine group (OR: 0.53; 95% CI: 0.31 to 0.90, P = 0.02). Conclusions: Dexmedetomidine administered perioperatively reduced postoperative atrial fibrillation, but was not effective in decreasing short and long-term mortality or cardiovascular complications in a Chinese population.