In this study, effects and side effects of application of rectal naproxen, combined with patient controlled intravenous morphine analgesia, were investigated in the elective coronary bypass operations for postoperative pain control, sedation and opioid use. Following the ethical committee approval and individual patient self consent, 40 patients, who underwent coronary artery bypass surgery were included in the study. A double blind study was performed by administering rectal naproxen to group N (n=20) and placebo to group P (n=20), at the end of the operation. Doses were repeated at the 12 th hour postoperatively.Patient controlled intravenous morphine analgesia was performed to all patients for postoperative 24 hours. Postoperative pain and sedation levels were assessed, the side effects were noted. There was no difference between two groups with respect to their demographic features duration of surgery, extubation time and side effects ( p>0.05). With respect to group P, decrease in opioid use, better sedation and decrease in pain scores during both resting and coughing was seen in group N (p<0.05). In conclusion, analgesia applied by addition of rectal naproxen to opioids achieved better pain management in selected patients after cardiac surgery.