Poor sleep quality is a common problem that can potentially predict mortality risk and quality of life in hemodialysis (HD) patients. Also, inflammation is a common feature in HD patients. To determine sleep quality and its correlation with serum C-reactive protein (CRP) level in these patients, we studied 132 chronic HD patients in two university-affiliated teaching hospitals in Sari, Iran during September 2010. Pittsburgh Sleep Quality Index was employed to assess the sleep quality of the patients in addition to CRP, albumin, cholesterol, phosphorus and hemoglobin levels. There were 104 (78.7%) patients who suffered from poor sleep quality. A significant correlation was found between serum CRP level and the patients' sleep quality (P <0.05). There was also a significant correlation between sleep quality and serum phosphorus and albumin levels and body mass index (P <0.05). Furthermore, a significant positive correlation existed between the different components of sleep quality and CRP (P <0.05). We conclude that there is a correlation between decreased sleep quality in HD patients and elevated CRP levels, which may have therapeutic implications.