Institutions with quality management programs need to evaluate the quality of perioperative pain management as well as other aspects of the health service. With the development of anesthesia-based pain services, improvement in this field has been reported. In this prospective study performed in a university hospital, we used a Postoperative Pain Therapy Assessment Questionnaire to quantify the effectiveness of pain therapy and factors affecting the degree of satisfaction and also to pinpoint areas that need improvement. A total of 915 patients who received patient-controlled analgesia for postoperative pain were included in the study; it seems to be the largest patient population from a single hospital. Data were collected as part of the hospital’s quality improvement activities. By analyzing the questionnaires, we found that patients were satisfied with the pain therapy performed under the guidance of anesthesiologists, but predictors of satisfaction such as pain intensity and side effects (nausea, vomiting, constipation and difficulty in walking) decreased patient satisfaction considerably. Patients are aware of the fact that health care givers take postoperative care seriously and they do not want any untoward effects interrupting their postoperative care. They are trying to participate in the decision making and also to learn more about pain medicine.