Knee osteoarthritis (OA) is common arthritis in elderly. Total knee arthroplasty; (TKA) is effective to restore mobility and improve quality of life in patients with OA. One of TKA complications is sleep disturbance.Aim was to evaluate sleep disturbance after TKA despite differences in postoperative pain managements.Prospective cohort study was performed on 67 patients who underwent primary TKA by different surgeons during May to March 2019. Samples were collected randomly from different hospitals in Sulaimani, Kurdistan, Iraq. Sleep pattern was assessed by Pittsburgh Sleep Quality Index (PSQI) and pain was assessed by visual analogue scale (VAS) for three months postoperatively.Mean ± standard deviation (SD) age (year) and body mass index (BMI; kg/m) of participants were 64.2 ± 7.5 (range: 40-82) and 27.3 ± 3.7 (range: 21.3-41.6), respectively. About 83.6% were females with male to female ratio of (0.2:1). There were statistically insignificant associations of age, gender, BMI, and history of diabetes mellitus with PSQI. Degree of pain was gradually decreasing during follow-up, but sleep was better at beginning followed by peaked disturbance after one month, then it started to improve gradually at end of follow-up.Sleep disturbance assessment needs multimodal approaches in order to improve it and satisfy patients.