Introduction : Chronic insomnia is a common complaint of hemodialysis patients. The present study has conducted to determine the effect of progressive muscle relaxation on insomnia severity of patients undergoing hemodialysis in hospitals affiliated with Shaheed Beheshti University of Medical Sciences in year 2010.

  Method : This study is a before and after quasi-experimental study. using purposive sampling method 42 patients were selected. Data collected by insomnia severity index (ISI) and two-week sleep diary that were completed before and after relaxation. Progressive muscle relaxation was trained to patients during three sessions and the patients did relaxation practice for a month, twice a day and filled relaxation diary after relaxation. Data were analyzed with t-test, willcoxon, macknemar, pearson and spearman tests.

  Result: More samples are female(54.5%), marreid(60%) and house keeper(54.2). mean age of samples are 42.83±12.85 and mean hemodialysis history were 4.97±4.54.

  The mean score of samples^, insomnia severity after relaxation(6.34±5.04) were significantly(P<0.001) lower than before(15.54±6.16) . the variables of sleep diary such as sleep onset duration, the number of awakening in night and real nocturnal sleep duration, showed significant deferences before and after relaxation (P<0.001).

  Conclusion : According to the results of this study, progressive muscle relaxation has a favorable effect on insomnia severity and sleep variables of hemodialysis patients and can be served as a useful method to improve sleep quality.