Background: Different measures of mortality and morbidity statistics is a good tool in determining the health status of a community،the health network development and application of methods of prevention and treatment. Basis of mortality data is the death certificate and the most important index in death certificate is accuracy of death causes with WHO standards and death causes codes in ICD10.WHO presents the rules and instructions on proper completion of death certificates, underlying cause of death and their coding approach. On the whole ICD10 has provided suitable preparation and internationally comparable statistics of deaths among countries that have adopted the standards promulgated by the WHO.

Methods: The study was observational cross-sectional and retrospective. The study population was patients at Sinai hospital in Tehran in the second 6 months of 2013.For data collection standard check list is used. Finally, after encoding the collected data and registration of them in SPSS software they were analyzed by using descriptive statistics and chi-square test.

Findings: Rate of death causes accuracy in death certificates issued based on the world health organization and the international classification of diseases was 66.2 percent. Most deaths have occurred among men aged over 70 years.30.5 percent of death occurred during hospitalization less than 24 hours. Emergency wards and ICU respectively with 33.5 percent and 29.6 percent have the highest mortality rate. The overall agreement between direct causes of death listed on death certificates and medical records was 0.68 and overall agreement between underlying causes of death listed on the death certificate with underlying causes recorded in the medical records was 0.64 which statistically classified in good level. Most accuracy of coding based on ICD10 chapters is related to the genitourinary system diseases (91%) and the lowest accuracy in circulatory system diseases (73%) has been recorded.

Conclusion: In this study the agreement between the initial and final diagnosis was low،which indicates a defect in the death certificates of death registration system. According to international standards announced by the WHO recording interval from onset to death should be given more attention. on the other hand, due to the importance of the cause of death on the standard death certificate, it is necessary to accurately detect these diagnosis and considering the general and specific rules defined in the international classification of diseases ,and  they be coded in order to analysis of indicators of mortality statistics.