The Insomnia Severity Index (ISI) is a Questionnaire to screen insomnia in clinics;so,it has been translated into many languages.

To determine the relaibility and validity of the Chinese Translation of Insomnia Severity Index(C-ISI) in patients with Insomnia and compare it with Chinese version of Pittsburgh Sleep Quality Index(C-PSQI).

To prove the relaibility and validity of C-ISI for using it in chinese speakers.

English version ISI was translated into Chinese base on standard guidelines then Chinese version was filled in 83 patients with insomnia as a clinical group and 45 persons without sleep complain as the control group by themselves in Neuropsychiatery Department of DongzhiMen hospital. For finding Test-Retest reliability they refilled ISI questionnaire 2 weeks later.

Cronbach-⍺ coefficient of C-ISI for the clinical group, control group and both of them was 0.72, 0.75 and 0.91 respectively. The C-ISI component and total scores in test were significantly correlated with their related components and total scores in re-test (P<0.05). Mean Ranks for All C-ISI components, total score were significantly higher in clinical group than control group that presents low sleep quality in clinical group. There are Significant correlations between C-ISI component and total scores and C-PSQI components and Total scores in related Items.

C-ISI has acceptable reliability and good sensitivity for assessing insomnia patients; besides, C-ISI can evaluate the insomnia patients similar to the PSQI-C so it can be used as a good scale to measure sleep quality in Chinese speakers.