Death and disease information are key information in priority setting. Because importance of valid and reliable mortality data, death registration system in I.R.Iran as a multi source registration system was established and improved from 1998. In this system mortality data are collected from hospitals, health houses and health centers, forensic medicine bureau, author­ized cemeteries, civil registration bureau and other probable sources in district and within a defined process data are col­lected in provincial health centers and then in ministry of health. For improvement of registered data some important activi­ties have to done in different level such as continuous education and strengthening intersectoral collaboration.