In this retrospective study, it was aimed to compare the effects of dexmedetomidine and morphine on postoperative pain, sedation, extubation time and hemodynamics in patients who underwent congenital cardiac surgery. Material and Methods: From December 2012 to December 2013, 46 patients between 1 to 5 years of age, who underwent congenital cardiac surgery were included and divided into two groups based on the sedative regimen used in the postoperative period. Twenty-three patients (Group Morp) received morphine at an infusion dose of 0.01 to 0.04 mg/kg/h; 23 patients (Group Dex) received dexmedetomidine at an infusion dose of 0.05 to 0.5 mcg/kg/h. Pain scores were measured using Children's Hospital Eastern Ontario Pain Scale (CHEOPS); sedation scores with the Ramsay Sedation Scale (RSS); and hemodynamic parameters were recorded with these measured values. Sedation debth was monitored by using the Bispectral Index (BIS). In this retrospective study, postoperative pain, sedation and hemodynamic effects of intravenous dexmedetomidine in pediatric patients undergoing congenital cardiac surgery, and the effects of mechanical ventilation duration and length of intensive care unit (ICU) stay were compared with morphine. Results: Mean doses of morphine and dexmedetomidine infused were 7.04±3.94 mg/24 h and 94.33±48.38 mcg/24 h, respectively. BIS values were higher in Group Dex than Group Morp (p<0.01). Mechanical ventilation duration was shorter in Group Dex compared to Group Morp 5.74±1.98 hours vs 7.83±3.08 hours) (p<0.05). The length of ICU stay and other outcome measurements between the two groups were similar. Heart rate was lower in the group Dex only in the first two hours (p<0.01). CHEOPS pain scores were similar in two groups (p> 0.05). RSS scores at 1 st , 2 nd , 3 rd , 4 th hours were higher in Group Dex than Group Morp (p <0.01); however, there was no difference between the groups in terms of RSS scores at the 12 th , 16 th , 20 th and 24 th hours (p> 0.05). There was no difference between the groups in terms of the frequency of side effects (p> 0.05). Conclusion: With regard to our study findings, dexmedetomidine can provide effective analgesia and sedation with shorter mechanical ventilation duration without adverse reaction compared to morphine in pediatric patients undergoing congenital cardiac surgery.