This descriptive, correlational study was conducted to determine orthopedic patients' night-time pain characteristics, their quality of sleep and the contributing factors to poor sleep experiences, and the relationship between pain and sleep. Data were collected by using the McGill Pain Questionnaire-SF (MPQ-SF) and Pittsburgh Sleep Quality Index (PSQI) on the second postoperative day. Data were analyzed using the SPSS version 10.0 for Windows. Mean age of the 75 patients was 49.55 +/- 21.10 years and were hospitalized in the orthopedic wards for 10.56 +/- 14.74 days. Of the sample, 65.3% were female and 36% had hip/knee arthroplasty surgery. Pain (45%) and noise (23%) were found to be the most cited factors affecting the sleep of patients in postoperative periods. They experienced "external" pain at the surgical site and verbalized their pain as "stabbing" and "tiring-exhausting." Patients' night-time pain was determined to be severe (6.59 +/- 1.62); their quality of sleep was also poor (9.24 +/- 3.53). A statistically significant correlation was found between patients' pain intensity and quality of sleep (p <= .05).